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  • richardmitnick 12:58 pm on December 5, 2019 Permalink | Reply
    Tags: "Icy Moons and Their Plumes", Astronomy, , , , , , , What is not at all common is liquid water   

    From Many Worlds: “Icy Moons and Their Plumes” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    From Many Worlds

    December 5, 2019
    Marc Kaufman

    1
    The existence of water or water vapor plumes on Europa has been studied for years, with a consensus view that they do indeed exist. Now NASA scientists have their best evidence so far that the moon does sporadically send water vapor into its atmosphere. (NASA/ESA/K. Retherford/SWRI)

    Just about everything that scientists see as essential for extraterrestrial life — carbon, hydrogen, oxygen, nitrogen, phosphorus, sulfur and sources of energy — is now known to be pretty common in our solar system and beyond. It’s basically there for the taking by untold potential forms of life.

    But what is not at all common is liquid water. Without liquid water Earth might well be uninhabited and today’s Mars, which was long ago significantly wetter, warmer and demonstrably habitable, is widely believed to be uninhabited because of the apparent absence of surface water (and all that deadly radiation, too.)

    This is a major reason why the discovery of regular plumes of water vapor coming out of the southern pole of Saturn’s moon Enceladus has been hailed as such a promising scientific development.

    NASA’s Solar System Exploration. Color image of icy Enceladus, the sixth-largest moon of Saturn

    The moon is pretty small, but most scientists are convinced it does have an under-ice global ocean that feeds the plume and just might support biology that could be collected during a flyby.

    But the moon of greatest scientific interest is Europa, one of the largest that orbits Jupiter.

    2
    Varied terrain on Europa. Credit: NASA/JPL-Caltech/SETI Institute

    It is now confidently described as having a sub-surface ocean below its crust of ice and — going back to science fiction writer extraordinaire Arthur C. Clarke — has often been rated the most likely body in our solar system to harbor extraterrestrial life.

    That is why it is so important that years of studying Europa for watery plumes has now paid off. While earlier observations strongly suggested that sporadic plumes of water vapor were in the atmosphere, only last month was the finding nailed, as reported in the journal Nature Astronomy.

    “While scientists have not yet detected liquid water directly, we’ve found the next best thing: water in vapor form,” said Lucas Paganini, a NASA planetary scientist who led the water detection investigation.

    3
    As this cutaway shows, vents in Europa’s icy crust could allow plumes of water vapor to escape from a sub-surface ocean. If observed up close, the chemical components of the plumes would be identified and could help explain the nature and history of the ocean below. ( NASA)

    The amount of water vapor found in the European atmosphere wasn’t great — about an Olympic-sized pool worth of H2O. Looking at the moon from the W. M. Keck Observatory in Hawaii, the scientists saw water molecules on the side of Europa that’s always facing in the direction of the moon’s orbit around Jupiter.

    Keck Observatory, operated by Caltech and the University of California, Maunakea Hawaii USA, 4,207 m (13,802 ft)

    But Paganini’s team registered the faint signal of water vapor just once throughout 17 nights of observations between 2016 and 2017

    That fact, Paganini said in a release, was significant. “For me,” he said, “the interesting thing about this work is not only the first direct detection of water above Europa, but also the lack (of more plumes found) within the limits of our detection method.”

    More advanced detection equipment certainly might find much more water in the atmosphere, and that possibility is where Europa eclipses Enceladus as the icy moon most likely to give up some of its closest kept secrets in the near term.

    Because in the next five years or so, not one but two major missions are scheduled to head for Europa — NASA’s Europa Clipper and the European Space Agency-led JUpiter ICy moons Explorer mission (JUICE.)

    NASA/Europa Clipper annotated

    ESA/Juice spacecraft depiction


    How the JUICE spacecraft will fly to the Jupiter system, using five gravity boosts along the way. (ESA)

    Although several missions have been proposed to return to Enceladus with more specialized instruments than the Cassini spacecraft had when it flew through a plumes in 2015, none have been formally approved and funded.

    NASA/ESA/ASI Cassini-Huygens Spacecraft

    JUICE is scheduled to launch first to Europa — as early as 2022. Because it will need multiple gravity boosts from other bodies to reach the Jupiter system, it is not expected to arrive before the late 2020s.

    As for the Europa Clipper, the launch date remains uncertain but estimated to be in the mid 2020s. If it can use the NASA’s super-heavy Space Launch System (SLS) for its launch, it could reach Jupiter and Europa before JUICE. But because of endless delays with the SLS development, and the desire to use its unique lift power if and when it becomes available for launches to our moon and elsewhere, the Clipper may well launch on a commercial rocket and need the same time-consuming boosts.

    The Europa Clipper and JUICE missions are different in many ways, but they do have the same Jupiter system and Europa destinations and so are in a race of sorts to be the first to taste Europa’s atmosphere up close.

    It’s a cooperative race for sure — NASA does have an instrument planned to ride on the JUICE mission — but who gets there first will be of some space-faring importance just because Europa has long been such a promising destination for scientists.

    Some Europa background:

    Forty years ago, a Voyager spacecraft snapped the first closeup images of Europa, one of Jupiter’s 79 moons.

    NASA/Voyager 2

    These revealed brownish cracks slicing the moon’s icy surface, which give Europa the look of an eyeball with criss-crossing veins. Missions to the outer solar system in the decades since have amassed enough additional information about Europa to make it a high-priority target of investigation in NASA’s search for life.

    For instance, NASA’s Galileo spacecraft, measured perturbations in Jupiter’s magnetic field near Europa while orbiting the gas giant planet.

    NASA/Galileo 1989-2003

    The measurements, taken between 1995 and 2003, suggested to scientists that electrically conductive fluid, likely a salty ocean beneath Europa’s ice layer, was causing the magnetic disturbances. When researchers analyzed the magnetic disturbances more closely in 2018, they found evidence of possible plumes.

    In the meantime, scientists announced in 2013 that they had used NASA’s Hubble Space Telescope to detect the chemical elements hydrogen (H) and oxygen (O) — components of water (H2O) — in plume-like configurations in Europa’s atmosphere. And a few years later, other scientists used Hubble to gather more evidence of possible plume eruptions when they snapped photos of finger-like projections that appeared in silhouette as the moon passed in front of Jupiter.

    Lorenz Roth, an astronomer and physicist from KTH Royal Institute of Technology in Stockholm who led the 2013 Hubble study and was a co-author of this recent investigation, said that detecting water vapor on other worlds is especially challenging.

    Existing spacecraft have limited capabilities to detect it, he said, and scientists using ground-based telescopes to look for water in deep space have to account for the distorting effect of water in Earth’s atmosphere. To minimize this effect, Paganini’s team used complex mathematical and computer modeling to simulate the conditions of Earth’s atmosphere so they could differentiate Earth’s atmospheric water from Europa’s in data returned by the Keck spectrograph.

    KECK Echellette Spectrograph and Imager (ESI)

    They used a spectrograph at the Keck Observatory that measures the chemical composition of planetary atmospheres through the infrared light they emit or absorb. Molecules such as water emit specific frequencies of infrared light as they interact with solar radiation.

    So while scientists had evidence that key ingredients for life, including liquid water, were present under Europa’s icy surface and that liquid geysers might sometimes erupt into the atmosphere, nobody had fully confirmed the presence of water in these plumes by directly measuring the water molecule itself. Until, that is, the recent confirmation by by scientists at NASA’s Goddard Space Flight Center and their international partners.

    The recent finding of a plume of water vapor in the Europan atmosphere will help scientists better understand the inner workings of the moon. Any lingering doubts have been alleviated about the presence of a liquid water ocean, possibly twice as large as Earth’s, beneath this moon’s miles-thick ice shell. And clearly and importantly, conditions in the ocean would have to be changeable, in some flux, if water is periodically pushed up to the surface and into the atmosphere.

    There are, of course, other theories of the source of the Europa plumes. Another is that that the water and vapor comes from shallow reservoirs of melted water ice not far below Europa’s surface. It’s also possible that Jupiter’s strong radiation field is stripping water particles from Europa’s ice shell, though the recent investigation argued against this mechanism as the source of the observed water.

    As Avi Mandell, a Goddard planetary scientist on Paganini’s team, put it:. “Eventually, we’ll have to get closer to Europa to see what’s really going on.”

    So if Europa is getting all this attention, why are there no parallel big missions planned to Enceladus? After all, the plumes (or geysers) coming out of the moon are known to be consistent and substantial.

    One mission was proposed for last year’s NASA New Frontiers class competition and was well received but ultimately not selected. The German Space Agency has been studying an Enceladus mission since 2012 and Breakthrough Initiative founder Yuri Milner, a Russian billionaire living in the United States, is working with a small NASA team on an simple, relatively inexpensive spacecraft to fly again through the plume and test for organic compounds and possibly by-products of biology.

    In effect, Milner and his colleagues believe the possibility of finding life on Enceladus is scientifically too tempting to wait for a full NASA effort — which appears unlikely while the costly Europa Clipper mission is under development.

    Briefly, the Enceladus geysers — which sometimes form a curtain of vapor –erupt from the moon’s south polar region. They were first interpreted as being the result of tidally produced pressure and heat in a subterranean sea, with fissures in the ice allowing the water and water vapor to escape. More recently, an even more intriguing source of the needed heat has been proposed.

    In 2017, an article in the journal Science by J. Hunter Waite of the Southwest Research Institute et al reported that measurements taken during Cassini mission’s final fly-through captured the presence of molecular hydrogen in the plumes. To planetary and Earth scientists, that particular hydrogen presence quite clearly means that the water shooting out from Enceladus is coming from an interaction between water and warmed rock minerals at the bottom of the moon’s ocean– and possibly from within hydrothermal vents.

    These chimney-like vents at the bottom of our oceans — coupled with a chemical mixture of elements and organic compounds similar to what has been detected in the plumes — are known on Earth as prime breeding grounds for life. One important reason why is that the hydrogen and hydrogen compounds produced in these settings are a source of energy, or food, for microbes.

    A logical conclusion of these findings: the odds that Enceladus harbors forms of simple life increased with the finding, though remain impossible to quantify.

    Less is known about the composition of the apparently far more sporadic plumes of Europa, but JUICE and the Europa Clipper will — if they arrive successfully — change that. They too may find a chemical soup conducive to life, and similar signs of deep ocean interactions between the salty ocean and rock minerals heated hydrothermally, through radiation, tidal pressures or perhaps all of the above.

    And, no doubt, the precious water and water vapor in those plumes will be the gateway to their understandings.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    About Many Worlds
    There are many worlds out there waiting to fire your imagination.

    Marc Kaufman is an experienced journalist, having spent three decades at The Washington Post and The Philadelphia Inquirer, and is the author of two books on searching for life and planetary habitability. While the “Many Worlds” column is supported by the Lunar Planetary Institute/USRA and informed by NASA’s NExSS initiative, any opinions expressed are the author’s alone.

    This site is for everyone interested in the burgeoning field of exoplanet detection and research, from the general public to scientists in the field. It will present columns, news stories and in-depth features, as well as the work of guest writers.

    About NExSS

    The Nexus for Exoplanet System Science (NExSS) is a NASA research coordination network dedicated to the study of planetary habitability. The goals of NExSS are to investigate the diversity of exoplanets and to learn how their history, geology, and climate interact to create the conditions for life. NExSS investigators also strive to put planets into an architectural context — as solar systems built over the eons through dynamical processes and sculpted by stars. Based on our understanding of our own solar system and habitable planet Earth, researchers in the network aim to identify where habitable niches are most likely to occur, which planets are most likely to be habitable. Leveraging current NASA investments in research and missions, NExSS will accelerate the discovery and characterization of other potentially life-bearing worlds in the galaxy, using a systems science approach.
    The National Aeronautics and Space Administration (NASA) is the agency of the United States government that is responsible for the nation’s civilian space program and for aeronautics and aerospace research.

    President Dwight D. Eisenhower established the National Aeronautics and Space Administration (NASA) in 1958 with a distinctly civilian (rather than military) orientation encouraging peaceful applications in space science. The National Aeronautics and Space Act was passed on July 29, 1958, disestablishing NASA’s predecessor, the National Advisory Committee for Aeronautics (NACA). The new agency became operational on October 1, 1958.

    Since that time, most U.S. space exploration efforts have been led by NASA, including the Apollo moon-landing missions, the Skylab space station, and later the Space Shuttle. Currently, NASA is supporting the International Space Station and is overseeing the development of the Orion Multi-Purpose Crew Vehicle and Commercial Crew vehicles. The agency is also responsible for the Launch Services Program (LSP) which provides oversight of launch operations and countdown management for unmanned NASA launches. Most recently, NASA announced a new Space Launch System that it said would take the agency’s astronauts farther into space than ever before and lay the cornerstone for future human space exploration efforts by the U.S.

    NASA science is focused on better understanding Earth through the Earth Observing System, advancing heliophysics through the efforts of the Science Mission Directorate’s Heliophysics Research Program, exploring bodies throughout the Solar System with advanced robotic missions such as New Horizons, and researching astrophysics topics, such as the Big Bang, through the Great Observatories [Hubble, Chandra, Spitzer, and associated programs. NASA shares data with various national and international organizations such as from the [JAXA]Greenhouse Gases Observing Satellite.

     
  • richardmitnick 11:40 am on December 5, 2019 Permalink | Reply
    Tags: "A newfound black hole in the Milky Way is weirdly heavy", Astronomy, , , , Gran Telescopio Canarias, , LAMOST telescope in China, , That’s not just a record- it’s also a conundrum., With a mass of about 68 suns it is far heftier than other stellar-mass black holes (those with masses below about 100 suns) in and around the Milky Way scientists say.   

    From Science News: “A newfound black hole in the Milky Way is weirdly heavy” 

    From Science News

    November 27, 2019
    Christopher Crockett

    1

    A black hole (one illustrated) with a mass equal to about 68 suns has been found in the Milky Way, researchers say. That dark mass is much heavier than other similar black holes. NAOJ

    A heavyweight black hole in our galaxy has some explaining to do.

    With a mass of about 68 suns, it is far heftier than other stellar-mass black holes (those with masses below about 100 suns) in and around the Milky Way, scientists say. That’s not just a record, it’s also a conundrum. According to theory, black holes in our galaxy that form from the explosive deaths of massive stars — as this one likely did — shouldn’t be heavier than about 25 suns.

    The black hole is locked in orbit with a young blue star dubbed LB-1, which sits about 13,800 light-years away in the constellation Gemini, researchers found. Combing through data from the LAMOST telescope in China, Jifeng Liu, an astrophysicist at the Chinese Academy of Sciences in Beijing, and colleagues noticed that LB-1 repeatedly moves toward and away from Earth with great speed — a sign that the star orbits something massive.

    LAMOST telescope located in Xinglong Station, Hebei Province, China

    With additional observations from telescopes in Hawaii and the Canary Islands, the team mapped out the orbit and deduced that the star gets whipped around by a dark mass roughly 68 times as massive as the sun. Only a black hole fits that description, the team reports November 27 in Nature.

    Keck Observatory, operated by Caltech and the University of California, Maunakea, Hawaii, USA.4,207 m (13,802 ft), above sea level,

    Gran Telescopio Canarias at the Roque de los Muchachos Observatory on the island of La Palma, in the Canaries, Spain, sited on a volcanic peak 2,267 metres (7,438 ft) above sea level

    “I never thought in my wildest dreams you could form a black hole this big [in the Milky Way],” says Michael Zevin, an astrophysicist at Northwestern University in Evanston, Ill. “If the observations pan out to be correct, this is really going to have people scratching their heads.”

    This black hole is not the heftiest in the Milky Way. That title goes to the behemoth in the center of the galaxy, a supermassive black hole in a class all its own with a mass of over 4 million suns. The mass of LB-1’s black hole is, however, on par with some of the black holes discovered recently by gravitational wave detectors, which sense ripples in spacetime from (among other things) merging pairs of black holes (SN: 2/17/16).

    But those black holes formed in far-off galaxies, probably in environments with a relative dearth of elements heavier than helium. The star LB-1 has a richer inventory of those elements, and presumably the star that formed its partner black hole had a similar stock. Stars with a greater abundance of heavy elements lose more of their mass to stellar winds, as those elements present a larger target to the radiation that drives those winds. Massive stars that form black holes also eject a lot of their mass during the supernova explosions that end their lives.

    “These two processes make very small black holes even out of very massive stars,” Liu says. But the black hole near LB-1 apparently didn’t get that memo.

    To make a black hole of 68 solar masses requires a reduction in the mass lost to stellar winds by a factor of five, Liu says. “We don’t know whether this is possible theoretically.”

    Alternatively, the black hole might have emerged from a failed supernova, an attempted stellar explosion that doesn’t have quite enough energy to hurl the star’s guts into space, leaving the gas to fall back into the black hole.

    The team also wonders if the black hole is the work of two stars. The scenario is speculative, Liu says, and “the odds are slim.” But in this story, LB-1 once orbited a snuggled-up pair of heftier stars that died and left behind two cores that merged into one black hole.

    It’s also possible that what appears to be a single 68-solar-mass black hole is actually two lighter black holes locked in a tight embrace. Such a pair would periodically nudge LB-1, giving it a subtle rocking motion that Liu and colleagues are searching for with other telescopes.

    Before getting caught up in potential origin stories, the observations need to be double-checked, Zevin cautions. “I wouldn’t put money down that it’s a definitive detection yet,” he says.

    The one catch, which the researchers do note, is that the calculated mass of the black hole depends on getting the distance to LB-1 correct. Their derived distance of 13,800 light-years — based on the star’s apparent brightness and calculations of its intrinsic luminosity — is about twice as far as the distance to the star determined by the Gaia satellite, a multiyear mission to create a precise 3-D map of over 1 billion stars in the Milky Way (SN: 5/9/18). If the Gaia distance is correct, then the black hole might be only 10 times as massive as the sun. (If the star is closer, then it’s less luminous, so less massive. That would mean that a lighter black hole is needed to explain the speed at which the star is getting whipped around.)

    That’s not necessarily a strike against the study. The researchers note that a much lower luminosity for the star would be at odds with its measured temperature. And if LB-1 is wobbling around a black hole, that would throw off the accuracy of the Gaia data, says Zevin. “But it is an important point that needs to be worked out.”

    See the full article here .


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    Please help promote STEM in your local schools.

    Stem Education Coalition

     
  • richardmitnick 11:12 am on December 5, 2019 Permalink | Reply
    Tags: "There's an Easy Trick to Telling Stars and Planets Apart in the Sky", Astronomy, , , ,   

    From Curiosity: “There’s an Easy Trick to Telling Stars and Planets Apart in the Sky” 

    Curiosity Makes You Smarter

    From From Curiosity

    January 25, 2018 [Just now in social media]
    Cody Gough

    Look up in the night sky, and you’ll see millions of stars and a handful of planets. How can you tell the difference? Just remember: The classic lullaby doesn’t go “twinkle, twinkle, little planet.” There’s a reason for that.
    Planet Light, Planet Bright, First Planet I See Tonight

    Stars twinkle because of the massive distance between them and Earth. And we mean massive: Our sun’s closest stellar neighbors are more than four light-years away. Because of that great distance, we essentially see each star as a single point of light — a shape with almost zero diameter. Once it hits Earth, that starlight is refracted by the various differences of temperature and density as it makes its way through our atmosphere. The refraction is greater than the star’s tiny diameter, so it’s easy to see — and to us, it looks like twinkling. The scientific term for this is astronomical scintillation.

    Our sun and the planets in our solar system are much closer than the rest of the stars in the sky. Earth’s atmosphere refracts light from those, too, but since they’re a lot closer to us, they show up with a larger diameter than those faraway stars. This makes them look more like tiny disks than pinpoints — something you might not notice with the naked eye but that’s easy to see with binoculars or a telescope. The light from one edge of that disk might be forced to “zig” in one direction, but light from the opposite side might “zag” in an opposite direction. Those opposing directions effectively cancel each other out, producing a steady shine that doesn’t twinkle like a little star.

    1

    Lost in Space

    Experienced stargazers can figure out which objects are stars and which are planets just by observing which ones twinkle and which ones don’t. But keep in mind that sometimes planets twinkle, too, if you spot them low in the sky. That’s because when you look toward the horizon, you’re looking through more atmosphere than when you’re looking straight up. This means more light refraction, which means more of that astronomical scintillation — aka twinkling.

    If you ever get a chance to visit outer space, of course, then you can expect to see a distinct lack of twinkling to go along with that distinct lack of atmosphere. The lack of light refraction from the atmosphere is why we put telescopes up in space, helping behemoths like the Hubble Space Telescope produce the brilliant and crisp images of the universe that make it famous. But that’s not the only difference you’ll notice in space.

    NASA astronaut James Reilly told SpaceFlight Insider that once your eyes adjust during a spacewalk, “you can start to notice that some of the stars have colors we don’t see here on the ground.

    So you see these pastel colors — light yellows, light pinks, light oranges, even light red ones and light blues — there’s all kinds of colors that you can see in these stars that you can’t see here because it’s filtered out by the atmosphere.”

    Twinkling Is in the Eye of the Beholder

    One other quirk of stargazing is that bright objects in the sky look different to everyone — even different telescopes. The four points emanating from stars in images from the Hubble Telescope, for example, happen in any telescope that focuses light with a mirror rather than with a lens. The four points are known as diffraction spikes and are caused by the light’s path being diffracted slightly as it passes by the cross-shaped struts that support the telescope’s secondary mirror.

    Distortion isn’t just for telescopes. Remember, the human eye has a lens, too! Those lenses have subtle structural imperfections called suture lines that show up where the lens fibers meet together. These imperfections leave a particular imprint on light as it reaches your eyes, so even though stars actually appear as tiny round dots, our lenses have smeared the light into a star-like shape by the time the light reaches our retinas. Because we’re all different, every eye on Earth will see a slightly different star-like smear depending on the exact nature of its suture lines; even your own left and right eyes will differ. But every eye sees the same shape for every single star. Try closing one eye the next time you’re looking up at the sky and see what happens!

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Curiosity Makes You Smarter

    Curiosity is on a mission to make learning easier and more fun than it has ever been. Our goal is to ignite curiosity and inspire people to learn. Each day, we create and curate engaging topics for millions of lifelong learners worldwide.

    Experience Curiosity on our website, through our apps and across social media. We designed Curiosity with your busy life in mind. Our editors find interesting and important topics that you’ll want to know more about, and introduce you to the best ways to keep learning.

    We hope you make Curiosity part of your daily digital diet. Never stop learning!

     
  • richardmitnick 9:51 am on December 5, 2019 Permalink | Reply
    Tags: "Looking for exoplanet life in all the right spectra", Astronomy, , , ,   

    From Cornell Chronicle: “Looking for exoplanet life in all the right spectra” 

    From Cornell Chronicle

    December 4, 2019
    Blaine Friedlander
    bpf2@cornell.edu

    1
    While astronomers don’t know what the Earth-like exoplanet Proxima b looks like, this artistic impression presents a view of the possible surface. New, upcoming large telescopes on Earth will soon explore atmospheres on exoplanets – like Proxima b – for signatures of life. ESO/M. Kornmesser

    A Cornell senior has come up with a way to discern life on exoplanets loitering in other cosmic neighborhoods: a spectral field guide.

    Zifan Lin ’20 has developed high-resolution spectral models and scenarios for two exoplanets that may harbor life: Proxima b, in the habitable zone of our nearest neighbor Proxima Centauri; and Trappist-1e, one of three possible Earth-like exoplanet candidates in the Trappist-1 system.

    Centauris Alpha Beta Proxima 27, February 2012. Skatebiker

    A size comparison of the planets of the TRAPPIST-1 system, lined up in order of increasing distance from their host star. The planetary surfaces are portrayed with an artist’s impression of their potential surface features, including water, ice, and atmospheres. NASA

    The paper, co-authored with Lisa Kaltenegger, associate professor of astronomy and director of Cornell’s Carl Sagan Institute, published Nov 18 in Monthly Notices of the Royal Astronomical Society.

    “In order to investigate whether there are signs of life on other worlds, it is very important to understand signs of life that show in a planet’s light fingerprint,” Lin said. “Life on exoplanets can produce a characteristic combination of molecules in its atmosphere – and those become telltale signs in the spectra of such planets.

    “In the near future we will be seeing the atmosphere of these worlds with new, sophisticated ground-based telescopes, which will allow us to explore the exoplanet’s climate and might spot its biota,” he said.

    In the search for habitable worlds, “M dwarf” stars catch astronomers’ eyes, since the local universe teems with these suns, which make up 75% of the nearby cosmos, according to Lin.

    Throughout the Milky Way, our home galaxy, astronomers have discovered more than 4,000 exoplanets, some in their own suns’ habitable zone – an area that provides conditions suitable for life.

    To explore the atmosphere of these places, scientists need large next-generation telescopes, such as the Extremely Large Telescope (ELT), currently under construction in northern Chile’s Atacama Desert;

    ESO/E-ELT,to be on top of Cerro Armazones in the Atacama Desert of northern Chile. located at the summit of the mountain at an altitude of 3,060 metres (10,040 ft).

    it is expected to be operational in 2025. Scientists can aim the mammoth eyepiece – with a flawless primary mirror about half the size of a football field – at Proxima b and Trappist-1e. The future telescope will have more than 250 times the light-gathering power of the Hubble Space Telescope.

    Lin and Kaltenegger said the high-resolution spectrographs from the ELT can discern water, methane and oxygen for both Proxima b and Trappist-1e, if these planets are like our own pale blue dot.

    About 4 light-years from Earth, Proxima b can be resolved by new ground-based telescopes, giving astronomers an edge in observing this close-by world.

    “Assuming these worlds could be like a young or modern Earth, with similar or eroded atmospheres,” Kaltenegger said. “Zifan has generated a database of light fingerprints for these worlds, a guide to allow observers to learn how to find signs of life, if they are there.

    Said Kaltenegger: “We are providing a template on how to find life on these worlds, if it exists.”

    Funding for this research was provided by the Carl Sagan Institute and the Breakthrough Foundation.

    See the full article here .


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    Please help promote STEM in your local schools.

    Stem Education Coalition

    Once called “the first American university” by educational historian Frederick Rudolph, Cornell University represents a distinctive mix of eminent scholarship and democratic ideals. Adding practical subjects to the classics and admitting qualified students regardless of nationality, race, social circumstance, gender, or religion was quite a departure when Cornell was founded in 1865.

    Today’s Cornell reflects this heritage of egalitarian excellence. It is home to the nation’s first colleges devoted to hotel administration, industrial and labor relations, and veterinary medicine. Both a private university and the land-grant institution of New York State, Cornell University is the most educationally diverse member of the Ivy League.

    On the Ithaca campus alone nearly 20,000 students representing every state and 120 countries choose from among 4,000 courses in 11 undergraduate, graduate, and professional schools. Many undergraduates participate in a wide range of interdisciplinary programs, play meaningful roles in original research, and study in Cornell programs in Washington, New York City, and the world over.

     
  • richardmitnick 9:36 am on December 5, 2019 Permalink | Reply
    Tags: "Composition of gas giant planets not determined by host star study finds", Astronomy, , , , ,   

    From UC Santa Cruz and Carnegie Institution for Science: “Composition of gas giant planets not determined by host star, study finds” 

    UC Santa Cruz

    From UC Santa Cruz

    and

    Carnegie Institution for Science
    Carnegie Institution for Science

    December 03, 2019
    Natasha Metzler, Carnegie
    stephens@ucsc.edu

    Research led by astronomers at UC Santa Cruz and Carnegie Institution for Science has implications for understanding how planets form.

    1
    An artist’s conception of a young star surrounded by a primordial rotating disk of gas and dust from which planets can form. (Illustration by Robin Dienel, courtesy of the Carnegie Institution for Science)

    A surprising analysis of the compositions of gas giant exoplanets and their host stars shows that there isn’t a strong correlation between their compositions when it comes to elements heavier than hydrogen and helium. The new findings, published in The Astronomical Journal, have important implications for understanding the planetary formation process.

    In their youths, stars are surrounded by a rotating disk of gas and dust from which planets are born. Astronomers have long wondered how much a star’s makeup determines the raw material from which planets are constructed—a question that is easier to probe now that we know the galaxy is teeming with exoplanets.

    “Understanding the relationship between the chemical composition of a star and its planets could help shed light on the planetary formation process,” explained first author Johanna Teske of the Carnegie Institution for Science.

    For example, previous research indicated that the occurrence of gas giant planets increases around stars with a higher concentration of heavy elements, those elements other than hydrogen and helium. This is thought to provide evidence for one of the primary competing theories for how planets form, which proposes that gas giant planets are built from the slow accretion of disk material until a core about 10 times Earth’s mass is formed. At this point, the solid baby planetary interior is able to surround itself with helium and hydrogen gas, birthing a mature giant planet.

    “Previous work looked at the relationship between the presence of planets and how much iron exists in the host star, but we wanted to expand that to include the heavy element content of the planets themselves, and to look at more than just iron,” explained co-author Daniel Thorngren, who completed much of the work as a graduate student at UC Santa Cruz and is now a Trottier Postdoctoral Fellow at the Université de Montréal.

    Teske, Thorngren and their colleagues—Jonathan Fortney of UC Santa Cruz, Natalie Hinkel of the Southwest Research Institute, and John Brewer of San Francisco State University—compared the bulk heavy element content of 24 cool, gas giant planets to the abundances of “planet forming elements” carbon, oxygen, magnesium, silicon, iron, and nickel in their 19 host stars (some stars host multiple planets).

    They were surprised to find that there was no correlation between the amount of heavy elements in these giant planets and the amount of these planet forming elements in their host stars. So how can astronomers explain the established trend that stars rich in heavy elements are more likely to host gas giant planets?

    “Unraveling this discrepancy could reveal new details about the planet formation process,” explained coauthor Fortney. “For example, what other factors are contributing to a baby planet’s composition as it forms? Perhaps its location in the disk and how far it is from any neighbors. More work is necessary to answer these crucial questions.”

    One clue may come from the authors’ combined results bundling the heavy elements into groupings that reflect their characteristics. The authors saw a tentative correlation between a planet’s heavy elements and its host star’s relative abundance of carbon and oxygen, which are called volatile elements, versus the rest of the elements included in this study, which fall into the group called refractory elements. These terms refer to the elements’ low boiling points (volatility) or their high melting points (in the case of the refractory elements). Volatile elements may represent an ice-rich planetary composition, whereas refractory elements may indicate a rocky composition.

    “I’m excited to explore this tentative result further, and hopefully add more information to our understanding of the relationships between star and planetary compositions from upcoming missions like NASA’s James Webb Space Telescope, which will be able to measure elements in exoplanet atmospheres,” Teske said.

    This work was supported by a NASA Hubble Fellowship and a NASA XRP grant.

    See the full article here .


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    Please help promote STEM in your local schools.

    Stem Education Coalition

    Carnegie Institution for Science

    Andrew Carnegie established a unique organization dedicated to scientific discovery “to encourage, in the broadest and most liberal manner, investigation, research, and discovery and the application of knowledge to the improvement of mankind…” The philosophy was and is to devote the institution’s resources to “exceptional” individuals so that they can explore the most intriguing scientific questions in an atmosphere of complete freedom. Carnegie and his trustees realized that flexibility and freedom were essential to the institution’s success and that tradition is the foundation of the institution today as it supports research in the Earth, space, and life sciences.

    The University of California, Santa Cruz, opened in 1965 and grew, one college at a time, to its current (2008-09) enrollment of more than 16,000 students. Undergraduates pursue more than 60 majors supervised by divisional deans of humanities, physical & biological sciences, social sciences, and arts. Graduate students work toward graduate certificates, master’s degrees, or doctoral degrees in more than 30 academic fields under the supervision of the divisional and graduate deans. The dean of the Jack Baskin School of Engineering oversees the campus’s undergraduate and graduate engineering programs.

    UCSC Lick Observatory, Mt Hamilton, in San Jose, California, Altitude 1,283 m (4,209 ft)

    .

    UC Observatories Lick Autmated Planet Finder, fully robotic 2.4-meter optical telescope at Lick Observatory, situated on the summit of Mount Hamilton, east of San Jose, California, USA

    The UCO Lick C. Donald Shane telescope is a 120-inch (3.0-meter) reflecting telescope located at the Lick Observatory, Mt Hamilton, in San Jose, California, Altitude 1,283 m (4,209 ft)

    UC Santa Cruz campus

    UCSC is the home base for the Lick Observatory.

    Lick Observatory's Great Lick 91-centimeter (36-inch) telescope housed in the South (large) Dome of main building
    Lick Observatory’s Great Lick 91-centimeter (36-inch) telescope housed in the South (large) Dome of main building

     
  • richardmitnick 3:21 pm on December 4, 2019 Permalink | Reply
    Tags: "Searching for Supernova Survivors", , Astronomy, , , , There are two kinds of Type Ia SNe both caused by white dwarfs hitting the Chandrasekhar mass limit — single degenerate (SD) and double degenerate (DD).   

    From astrobites: “Searching for Supernova Survivors” 

    Astrobites bloc

    From astrobites

    12.4.19 from AAS NOVA
    Lauren Sgro

    1
    Artist’s impression of a supernova. Could some companions survive these powerful explosions? [ESO/M. Kornmesser]

    Title: Search for Surviving Companions of Progenitors of Young LMC Type Ia Supernovae Remnants
    Authors: Chuan–Jui Li et al.
    First Author’s Institution: National Taiwan University
    3
    Status: Accepted to ApJ

    Supernovae Survivors?

    Surviving a supernova (SN) may sound crazy, since supernovae (SNe) are among the most energetic events in space. Type Ia SNe result from the explosions of white dwarfs, and just one of these events can temporarily outshine an entire galaxy. So how could anything survive such an explosion?

    Well, there are two kinds of Type Ia SNe, both caused by white dwarfs hitting the Chandrasekhar mass limit — single degenerate (SD) and double degenerate (DD). DD Type Ia Sne are caused by the merger of two white dwarfs that, upon merging, will pretty much annihilate one another and cause a SN. However, a SD Type Ia SN only involves one white dwarf. In this case, there is no merger; instead, the white dwarf has a non-degenerate (a.k.a., not a white dwarf) companion from which it has drawn too much mass, causing the white dwarf to explode. Since only one star (called the “progenitor”) is doing the exploding in this SD scenario, perhaps that companion will live long enough to tell its story…

    3
    Figure 1: SN 0519–69.0. The authors fit the SN shell in Hα (taken by HST) to an ellipse marked in white, with the white cross at its center. Averaging this with the center determined by another publication, the authors take the red ‘x’ as the explosion center. The red dashed circle marks the runaway distance for a MS companion (0.2 pc) and the cyan circle marks this distance for helium companions (0.6 pcs). The green circle denotes the search radius for background stars taken between the cyan and green circles. Similar figures for the other supernovae are available in the paper. [Li et al. 2019]

    Searching for a Companion

    The authors of today’s paper set out to look for potential companions dancing around SN remnants, the shells of material left over by SN explosions. The sought-after companions, which could be main sequence (MS) stars, red-giant stars, or helium stars, may have lost their outer layers in the deadly explosion but could live on as a dense core. These surviving cores should be identifiable — they probably move differently as a result of the explosion, and they likely look different in color.

    Knowing that these companion cores will stand out from background stars, the authors choose three Type Ia supernovae remnants to investigate for survivors: SN 0519–69.0, DEML71, and SN 0548–70.4. Because SN remnants in our own galaxy can be tough to look at through the galactic plane, these remnants are all located in the Large Magellanic Cloud (LMC).

    Large Magellanic Cloud. Adrian Pingstone December 2003

    The first two SNe on the list have been examined before with no luck, but the authors hope that their new Hubble Space Telescope data will shed new light on these areas of the sky.

    Today’s authors use those two methods, analyzing the color and the motion of stars surrounding the chosen SNe to search for surviving companions. Before they can do this though, they need to determine a proper area to search.

    Where to Look?

    SNe remnants have a generally circular or elliptical shape, as the shock from the explosion propagates outward in all directions and interacts with the interstellar medium. By finding the geometrical center of the remnant’s visible shell, the authors estimate an explosion site (see Figure 1).

    If a star survives a SN explosion, its velocity after the supernova should be the sum of its own orbital velocity and the velocity of the progenitor’s translational velocity. Previous studies have determined the maximum speed that a MS or helium star could be traveling after a Type Ia SN. Using these velocities, the authors calculate just how far a companion core could have traveled away from the SN center since the explosion and narrow their search for survivors to this area (called the “runaway distance”). And of course, there has to be a control — the authors determine a set of background stars to which they can compare their potential survivors (see Figures 1 & 2).

    4
    Figure 2: SN 0519–69.0. Stars with V mag < 23.0 (most likely cutoff for potential companions from Schaefer et al. 2012) that lie within the runaway bounds. These are analyzed as potential survivors in the CMDs and RV plots. Red for MS, cyan for helium stars. [Li et al. 2019]

    Method 1: Examining Color

    To examine the color of their potential survivors, the authors plot the stars’ colors and absolute magnitudes on a very useful diagram called a color–magnitude diagram (clever name, right?). Included on these plots are all the candidate companions and background stars, as well as several “post-impact evolutionary tracks” (see Figure 3). These tracks are merely paths on the diagram that show how a MS or helium companion star, after a SN explosion, should change in color (which depends on its temperature) and brightness according to its initial mass. Therefore, if there are any true surviving companions, they should lie on these tracks.

    You may have noticed that red-giant stars, although a potential type of companion, have not been included in the search up to this point. Astronomers do not yet have evolutionary tracks for red giants, unfortunately. More on why that is unfortunate in just a second.

    5
    Figure 3: CMDs for SN 0519–69.0. Left: The HST equivalent of a V vs B–V CMD. Right: The HST equivalent of an I vs V-I CMD. Evolutionary tracks are shown in green, with the helium star tracks situated in the left of each diagram. [Li et al. 2019]

    Method 2: Examining Motion

    The second method for identifying surviving companions is to examine their radial velocity (RV), the speed of their motion away from or towards the Earth. Astronomers need spectral data to get this, which the authors only have for SN 0519–69.0 and DEML71. Now, although we don’t have a great idea of what that RV should be, it clearly should be different from the RV of background stars not involved in the SNe. The authors look at the distributions of RVs for relevant stars (candidates or candidates+background — Figure 4) to determine which stars have abnormal RVs, and these are considered candidate survivors.

    6
    Figure 4: RV for stars with V mag < 21.6 (limiting magnitude for reliable spectral fits). For SN 0519–69.0, there were only a few candidates, so the authors included the background stars to establish a distribution. Star #5 is the strange one — it is not moving with the rest of the group! Again, the same figures for the other SNe are available in the paper. [Li et al. 2019]

    Results

    So what came of this survivor search? Let’s take a look at each supernova.

    SN 0519-69.0: The CMD search did not return any potential companions. The stars within the runaway radii have colors that do not fall on one of the corresponding evolutionary tracks. However, there is a star with a strange (> 2.5σ away from the mean) RV, as shown in Figure 4. This oddball star may be considered a candidate if it also fell on the evolutionary tracks, but it does not. Why, you ask? Well, it seems that this star is likely a red giant, as it falls on the red giant branch in the CMDs. So, this star could very well be a candidate, but red-giant evolutionary tracks must be developed for the authors to confirm either way (that’s the unfortunate part).

    DEML71: This SN has a very similar story to SN 0519-69.0. No stars can be considered candidates from the CMDs, but there is indeed a star with a strange RV. However, as we saw before, it seems to be a red giant and therefore cannot be considered a candidate due to the lack of theoretical data. Boo.

    SN 0548-70.4: Inspection of the CMDs show that there is indeed a star that falls on one of the MS evolutionary tracks! Great! … But wait… there’s more. This star does not appear on evolutionary tracks for both colors, so the authors remain skeptical — a true candidate should fall on tracks for both CMDs. Furthermore, the part of the evolutionary track that the candidate does fall on indicates an age of only ~110 years. This SN remnant is about 10,000 years old, so obviously this star is unrelated to the explosion and is likely not the candidate the authors were looking for.

    As with all science, null results are still results. Even though no surviving cores were identified, the authors still gained valuable information — like, we really need some red-giant post-impact evolutionary tracks. Or perhaps these SNe are not what they seem; if the SD and DD models are drastic oversimplifications, then our predictions for them won’t lead us to surviving stars. Many other types of Type 1a supernova have been proposed, such as sub-/super-Chandrasekhar or spin-up/spin-down. All in all, astronomers rely on models quite often, since we can’t go grab a star. With comparison to more models, we will have a better picture of reality.

    See the full article here .


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    Please help promote STEM in your local schools.

    Stem Education Coalition

    What do we do?

    Astrobites is a daily astrophysical literature journal written by graduate students in astronomy. Our goal is to present one interesting paper per day in a brief format that is accessible to undergraduate students in the physical sciences who are interested in active research.
    Why read Astrobites?

    Reading a technical paper from an unfamiliar subfield is intimidating. It may not be obvious how the techniques used by the researchers really work or what role the new research plays in answering the bigger questions motivating that field, not to mention the obscure jargon! For most people, it takes years for scientific papers to become meaningful.
    Our goal is to solve this problem, one paper at a time. In 5 minutes a day reading Astrobites, you should not only learn about one interesting piece of current work, but also get a peek at the broader picture of research in a new area of astronomy.

     
  • richardmitnick 2:52 pm on December 4, 2019 Permalink | Reply
    Tags: "A New Theory for How Black Holes and Neutron Stars Shine Bright", Astronomy, , , , , ,   

    From Columbia University: “A New Theory for How Black Holes and Neutron Stars Shine Bright” 

    Columbia U bloc

    From Columbia University

    November 28, 2019
    Carla CantorCarla Cantor
    Director of Communications, Science and Technology
    +1 212 854 5276
    carla.cantor@columbia.edu

    Columbia researchers suggest radiation that lights the densest objects in our universe is powered by the interplay of turbulence and reconnection of super-strong magnetic fields.

    1
    Crab Nebula. Image: NASA, ESA, J. Hester (Arizona State University)

    For decades, scientists have speculated about the origin of the electromagnetic radiation emitted from celestial regions that host black holes and neutron stars—the most mysterious objects in the universe.

    Astrophysicists believe that this high-energy radiation, which makes neutron stars and black holes shine bright, is generated by electrons that move at nearly the speed of light, but the process that accelerates these particles has remained a mystery.

    Now, researchers at Columbia University have presented a new explanation for the physics underlying the acceleration of these energetic particles.

    In a study published in the December issue of The Astrophysical Journal, astrophysicists Luca Comisso and Lorenzo Sironi employed massive super-computer simulations to calculate the mechanisms that accelerate these particles.

    3
    Columbia Habanero supercomputer

    UCSC Pleiades SGI supercomputer

    NERSC Cray Cori II supercomputer at NERSC at LBNL, named after Gerty Cori, the first American woman to win a Nobel Prize in science

    LBL NERSC Cray XC30 Edison supercomputer

    TACC DELL EMC Stampede2 supercomputer

    ORNL Cray XK7 Titan Supercomputer, once the fastest in the world, to be decommissioned

    They concluded that their energization is a result of the interaction between chaotic motion and reconnection of super-strong magnetic fields.

    “Turbulence and magnetic reconnection—a process in which magnetic field lines tear and rapidly reconnect—conspire together to accelerate particles, boosting them to velocities that approach the speed of light,” said Comisso, a postdoctoral research scientist at Columbia and first author on the study.

    “The region that hosts black holes and neutron stars is permeated by an extremely hot gas of charged particles, and the magnetic field lines dragged by the chaotic motions of the gas, drive vigorous magnetic reconnection,” he added. “It is thanks to the electric field induced by reconnection and turbulence that particles are accelerated to the most extreme energies, much higher than in the most powerful accelerators on Earth, like the Large Hadron Collider at CERN.”

    When studying turbulent gas, scientists cannot predict chaotic motion precisely. Dealing with the mathematics of turbulence is difficult, and it constitutes one of the seven “Millennium Prize” mathematical problems. To tackle this challenge from an astrophysical point of view, Comisso and Sironi designed extensive super-computer simulations—among the world’s largest ever done in this research area—to solve the equations that describe the turbulence in a gas of charged particles.

    “We used the most precise technique—the particle-in-cell method—for calculating the trajectories of hundreds of billions of charged particles that self-consistently dictate the electromagnetic fields. And it is this electromagnetic field that tells them how to move,” said Sironi, assistant professor of astronomy at Columbia and the study’s principal investigator.

    Sironi said that the crucial point of the study was to identify role magnetic reconnection plays within the turbulent environment The simulations showed that reconnection is the key mechanism that selects the particles that will be subsequently accelerated by the turbulent magnetic fields. They also revealed that particles gained most of their energy by bouncing randomly at an extremely high speed. When the magnetic field is strong, this acceleration mechanism is very rapid. But the strong fields also force the particles to travel in a curved path, and by doing so, they emit electromagnetic radiation.

    “This is indeed the radiation emitted around black holes and neutron stars that make them shine, a phenomenon we can observe on Earth,” Sironi said.

    The ultimate goal, the researchers said, is to get to know what is really going on in the extreme environment surrounding black holes and neutron stars, which could shed additional light on fundamental physics and improve our understanding of how our universe works.

    They plan to connect their work even more firmly by comparing their predictions with the electromagnetic spectrum emitted from the Crab Nebula, the most intensely studied bright remnant of a supernova (a star that violently exploded in the year 1054).

    “We figured out an important connection between turbulence and magnetic reconnection for accelerating particles, but there is still so much work to be done,” Comisso said. “Advances in this field of research are rarely the contribution of a handful of scientists, but they are the result of a large collaborative effort.”

    Other researchers, such as the Plasma Astrophysics group at the University of Colorado Boulder, are making important contributions in this direction, Comisso said.

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    Columbia U Campus

    Columbia University was founded in 1754 as King’s College by royal charter of King George II of England. It is the oldest institution of higher learning in the state of New York and the fifth oldest in the United States.

     
  • richardmitnick 1:59 pm on December 4, 2019 Permalink | Reply
    Tags: Among the findings are new understandings of how the Sun's constant outflow of solar wind behaves., Astronomy, , , , First NASA Parker Solar Probe Results Reveal Surprising Details About Our Sun, , , Switchbacks   

    From NASA Parker Solar Probe: “First NASA Parker Solar Probe Results Reveal Surprising Details About Our Sun” 

    NASA image

    NASA Parker Solar Probe Plus named to honor Pioneering Physicist Eugene Parker

    From NASA Parker Solar Probe

    Dec. 4, 2019

    Grey Hautaluoma
    Headquarters, Washington
    202-358-0668
    grey.hautaluoma-1@nasa.gov

    Karen Fox
    Headquarters, Washington
    301-286-6284
    karen.fox@nasa.gov


    The WISPR image on NASA’s Parker Solar Probe captured imagery of the constant outflow of material from the Sun during its close approach to the Sun in April 2019. Credits: NASA/NRL/APL

    The Sun is revealing itself in dramatic detail and shedding light on how other stars may form and behave throughout the universe – all thanks to NASA’s Parker Solar Probe. The spacecraft is enduring scorching temperatures to gather data, which are being shared for the first time in four new papers that illuminate previously unknown and only-theorized characteristics of our volatile celestial neighbor.

    The information Parker has uncovered about how the Sun constantly ejects material and energy will help scientists rewrite the models they use to understand and predict the space weather around our planet, and understand the process by which stars are created and evolve. This information will be vital to protecting astronauts and technology in space – an important part of NASA’s Artemis program, which will send the first woman and the next man to the Moon by 2024 and, eventually, on to Mars.

    The four papers, now available online from the journal Nature, describe Parker’s unprecedented near-Sun observations through two record-breaking close flybys. They reveal new insights into the processes that drive the solar wind – the constant outflow of hot, ionized gas that streams outward from the Sun and fills up the solar system – and how the solar wind couples with solar rotation. Through these flybys, the mission also has examined the dust of the coronal environment, and spotted particle acceleration events so small that they are undetectable from Earth, which is nearly 93 million miles from the Sun.

    During its initial flybys, Parker studied the Sun from a distance of about 15 million miles. That is already closer to the Sun than Mercury, but the spacecraft will get even closer in the future, as it travels at more than 213,000 mph, faster than any previous spacecraft.

    “This first data from Parker reveals our star, the Sun, in new and surprising ways,” said Thomas Zurbuchen, associate administrator for science at NASA Headquarters in Washington. “Observing the Sun up close rather than from a much greater distance is giving us an unprecedented view into important solar phenomena and how they affect us on Earth, and gives us new insights relevant to the understanding of active stars across galaxies. It’s just the beginning of an incredibly exciting time for heliophysics with Parker at the vanguard of new discoveries.”

    Among the findings are new understandings of how the Sun’s constant outflow of solar wind behaves. Seen near Earth, the solar wind plasma appears to be a relatively uniform flow – one that can interact with our planet’s natural magnetic field and cause space weather effects that interfere with technology. Instead of that flow, near the Sun, Parker’s observations reveal a dynamic and highly structured system, similar to that of an estuary that serves as a transition zone as a river flows into the ocean. For the first time, scientists are able to study the solar wind from its source, the Sun’s corona, similar to how one might observe the stream that serves as the source of a river. This provides a much different perspective as compared to studying the solar wind were its flow impacts Earth.

    2
    NASA’s Parker Solar Probe observed a slow solar wind flowing out from the small coronal hole – the long, thin black spot seen on the left side of the Sun in this image captured by NASA’s Solar Dynamics Observatory – on October 27, 2018. While scientists have long known that fast solar wind streams flow from coronal holes near the poles, they have not yet conclusively identified the source of the Sun’s slow solar wind. Credits: NASA/SDO

    NASA/SDO

    Switchbacks

    One type of event in particular caught the attention of the science teams – flips in the direction of the magnetic field, which flows out from the Sun, embedded in the solar wind and detected by the FIELDS instrument. These reversals – dubbed “switchbacks” – appear to be a very common phenomenon in the solar wind flow inside the orbit of Mercury, and last anywhere from a few seconds to several minutes as they flow over the spacecraft. Yet they seem not to be present any farther from the Sun, making them undetectable without flying directly through that solar wind the way Parker has.

    During a switchback, the magnetic field whips back on itself until it is pointed almost directly back at the Sun. These switchbacks, along with other observations of the solar wind, may provide early clues about what mechanisms heat and accelerate the solar wind. Not only does such information help change our understanding of what causes the solar wind and space weather affecting Earth, it also helps us understand a fundamental process of how stars work and how they release magnetic energy into their environment.

    Rotating Wind

    In a separate publication, based on measurements by the Solar Wind Electrons Alphas and Protons (SWEAP) instrument, researchers found surprising clues as to how the Sun’s rotation affects the outflow of the solar wind. Near Earth, the solar wind flows past our planet as if it travels initially in almost straight lines – or “radially,” like spokes on a bicycle wheel – out from the Sun in all directions. But the Sun rotates as it releases the solar wind, and before it breaks free, the solar wind is expected to get a push in sync with the Sun’s rotation.

    As Parker ventured to a distance of around 20 million miles from the Sun, researchers obtained their first observations of this effect. Here, the extent of this sideways motion was much stronger than predicted, but it also transitioned more quickly than predicted to a straight, strictly outward flow, which helps mask the effects at a larger distance. This enormous extended atmosphere of the Sun will naturally affect the star’s rotation. Understanding this transition point in the solar wind is key to helping us understand how the Sun’s rotation slows down over time, with implications for the lifecycles of our star, its potentially violent past, as well as other stars and the formation of protoplanetary disks, dense disks of gas and dust encircling young stars.

    Dust in the Wind

    Parker also observed the first direct evidence of dust starting to thin out around 7 million miles from the Sun – an effect that has been theorized for nearly a century, but has been impossible to measure until now. These observations were made using Parker’s Wide-field Imager for Solar Probe (WISPR) instrument, at a distance of about 4 million miles from the Sun. Scientists have long suspected that close to the Sun, this dust would be heated to high temperatures, turning it into a gas and creating a dust-free region around the star. At the observed rate of thinning, scientists expect to see a truly dust-free zone beginning at a distance of about 2-3 million miles from the Sun, which the spacecraft could observe as early as September 2020, during its sixth flyby. That dust-free zone would signal a place where the material of the dust has been evaporated by the Sun’s heat, to become part of the solar wind flying past Earth.

    Energetic Particles

    Finally, Parker’s Integrated Science Investigation of the Sun (ISʘIS) energetic particle instruments have measured several never-before-seen events so small that all traces of them are lost before they reach Earth. These instruments have also measured a rare type of particle burst with a particularly high ratio of heavier elements – suggesting that both types of events may be more common than scientists previously thought. Solar energetic particle events are important, as they can arise suddenly and lead to space weather conditions near Earth that can be potentially harmful to astronauts. Unraveling the sources, acceleration and transport of solar energetic particles will help us better protect humans in space in the future.

    “The Sun is the only star we can examine this closely,” said Nicola Fox, director of the Heliophysics Division at NASA Headquarters. “Getting data at the source already is revolutionizing our understanding of our own star and stars across the universe. Our little spacecraft is soldiering through brutal conditions to send home startling and exciting revelations.”

    Data from Parker Solar Probe’s first two solar encounters are available online at:

    https://go.nasa.gov/34VPMGK

    For more information about Parker, visit:

    https://www.nasa.gov/parker

    Imagery from the mission is available at:

    https://svs.gsfc.nasa.gov/13484

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Parker Solar Probe is part of NASA’s Living with a Star program to explore aspects of the Sun-Earth system that directly affect life and society. The Living with a Star program is managed by the agency’s Goddard Space Flight Center in Greenbelt, Maryland, for NASA’s Science Mission Directorate in Washington. Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, designed, built and operates the spacecraft.

    For more information about Parker, visit:

    https://www.nasa.gov/parker

    The National Aeronautics and Space Administration (NASA) is the agency of the United States government that is responsible for the nation’s civilian space program and for aeronautics and aerospace research.

    President Dwight D. Eisenhower established the National Aeronautics and Space Administration (NASA) in 1958 with a distinctly civilian (rather than military) orientation encouraging peaceful applications in space science. The National Aeronautics and Space Act was passed on July 29, 1958, disestablishing NASA’s predecessor, the National Advisory Committee for Aeronautics (NACA). The new agency became operational on October 1, 1958.

    Since that time, most U.S. space exploration efforts have been led by NASA, including the Apollo moon-landing missions, the Skylab space station, and later the Space Shuttle. Currently, NASA is supporting the International Space Station and is overseeing the development of the Orion Multi-Purpose Crew Vehicle and Commercial Crew vehicles. The agency is also responsible for the Launch Services Program (LSP) which provides oversight of launch operations and countdown management for unmanned NASA launches. Most recently, NASA announced a new Space Launch System that it said would take the agency’s astronauts farther into space than ever before and lay the cornerstone for future human space exploration efforts by the U.S.

    NASA science is focused on better understanding Earth through the Earth Observing System, advancing heliophysics through the efforts of the Science Mission Directorate’s Heliophysics Research Program, exploring bodies throughout the Solar System with advanced robotic missions such as New Horizons, and researching astrophysics topics, such as the Big Bang, through the Great Observatories [Hubble, Chandra, Spitzer, and associated programs. NASA shares data with various national and international organizations such as from the [JAXA]Greenhouse Gases Observing Satellite.

     
  • richardmitnick 1:27 pm on December 4, 2019 Permalink | Reply
    Tags: "First Giant Planet around White Dwarf Found", Astronomy, , , ,   

    From European Southern Observatory: “First Giant Planet around White Dwarf Found” 

    ESO 50 Large

    From European Southern Observatory

    4 December 2019
    Boris Gänsicke
    University of Warwick
    UK
    Tel: +44 247 657 4741
    Email: boris.gaensicke@warwick.ac.uk

    Matthias Schreiber
    Valparaiso University
    Chile
    Tel: +56 32 299 5518
    Email: matthias.schreiber@uv.cl

    Odette Toloza
    University of Warwick
    UK
    Email: odette.toloza@warwick.ac.uk

    Nicola Gentile Fusillo (study co-author)
    European Southern Observatory and University of Warwick
    Germany
    Tel: +49 8932 0067 50
    Cell: +44 7476 9595 49
    Email: ngentile@eso.org

    Christopher Manser (study co-author)
    University of Warwick
    UK
    Tel: +44 7516 8167 53
    Email: c.manser@warwick.ac.uk

    Bárbara Ferreira
    ESO Public Information Officer
    Garching bei München, Germany
    Tel: +49 89 3200 6670
    Email: pio@eso.org

    ESO observations indicate the Neptune-like exoplanet is evaporating.

    1
    Researchers using ESO’s Very Large Telescope [below]have, for the first time, found evidence of a giant planet associated with a white dwarf star. The planet orbits the hot white dwarf, the remnant of a Sun-like star, at close range, causing its atmosphere to be stripped away and form a disc of gas around the star. This unique system hints at what our own Solar System might look like in the distant future.

    “It was one of those chance discoveries,” says researcher Boris Gänsicke, from the University of Warwick in the UK, who led the study, published today in Nature. The team had inspected around 7000 white dwarfs observed by the Sloan Digital Sky Survey and found one to be unlike any other.

    SDSS Telescope at Apache Point Observatory, near Sunspot NM, USA, Altitude2,788 meters (9,147 ft)

    By analysing subtle variations in the light from the star, they found traces of chemical elements in amounts that scientists had never before observed at a white dwarf. “We knew that there had to be something exceptional going on in this system, and speculated that it may be related to some type of planetary remnant.”

    To get a better idea of the properties of this unusual star, named WDJ0914+1914, the team analysed it with the X-shooter instrument on ESO’s Very Large Telescope in the Chilean Atacama Desert.

    ESO X-shooter on VLT on UT2 at Cerro Paranal, Chile

    These follow-up observations confirmed the presence of hydrogen, oxygen and sulphur associated with the white dwarf. By studying the fine details in the spectra taken by ESO’s X-shooter, the team discovered that these elements were in a disc of gas swirling into the white dwarf, and not coming from the star itself.

    “It took a few weeks of very hard thinking to figure out that the only way to make such a disc is the evaporation of a giant planet,” says Matthias Schreiber from the University of Valparaiso in Chile, who computed the past and future evolution of this system.

    The detected amounts of hydrogen, oxygen and sulphur are similar to those found in the deep atmospheric layers of icy, giant planets like Neptune and Uranus. If such a planet were orbiting close to a hot white dwarf, the extreme ultraviolet radiation from the star would strip away its outer layers and some of this stripped gas would swirl into a disc, itself accreting onto the white dwarf. This is what scientists think they are seeing around WDJ0914+1914: the first evaporating planet orbiting a white dwarf.

    Combining observational data with theoretical models, the team of astronomers from the UK, Chile and Germany were able to paint a clearer image of this unique system. The white dwarf is small and, at a blistering 28 000 degrees Celsius (five times the Sun’s temperature), extremely hot. By contrast, the planet is icy and large—at least twice as large as the star. Since it orbits the hot white dwarf at close range, making its way around it in just 10 days, the high-energy photons from the star are gradually blowing away the planet’s atmosphere. Most of the gas escapes, but some is pulled into a disc swirling into the star at a rate of 3000 tonnes per second. It is this disc that makes the otherwise hidden Neptune-like planet visible.

    “This is the first time we can measure the amounts of gases like oxygen and sulphur in the disc, which provides clues to the composition of exoplanet atmospheres,” says Odette Toloza from the University of Warwick, who developed a model for the disc of gas surrounding the white dwarf.

    “The discovery also opens up a new window into the final fate of planetary systems,” adds Gänsicke.

    Stars like our Sun burn hydrogen in their cores for most of their lives. Once they run out of this fuel, they puff up into red giants, becoming hundreds of times larger and engulfing nearby planets. In the case of the Solar System, this will include Mercury, Venus, and even Earth, which will all be consumed by the red-giant Sun in about 5 billion years. Eventually, Sun-like stars lose their outer layers, leaving behind only a burnt-out core, a white dwarf. Such stellar remnants can still host planets, and many of these star systems are thought to exist in our galaxy. However, until now, scientists had never found evidence of a surviving giant planet around a white dwarf. The detection of an exoplanet in orbit around WDJ0914+1914, located about 1500 light years away in the constellation of Cancer, may be the first of many orbiting such stars.

    According to the researchers, the exoplanet now found with the help of ESO’s X-shooter orbits the white dwarf at a distance of only 10 million kilometres, or 15 times the solar radius, which would have been deep inside the red giant. The unusual position of the planet implies that at some point after the host star became a white dwarf, the planet moved closer to it. The astronomers believe that this new orbit could be the result of gravitational interactions with other planets in the system, meaning that more than one planet may have survived its host star’s violent transition.

    “Until recently, very few astronomers paused to ponder the fate of planets orbiting dying stars. This discovery of a planet orbiting closely around a burnt-out stellar core forcefully demonstrates that the Universe is time and again challenging our minds to step beyond our established ideas,” concludes Gänsicke.

    More information

    The team is composed of Boris Gänsicke (Department of Physics & Centre for Exoplanets and Habitability, University of Warwick, UK), Matthias Schreiber (Institute of Physics and Astronomy, Millennium Nucleus for Planet Formation, Valparaiso University, Chile), Odette Toloza (Department of Physics, University of Warwick, UK), Nicola Gentile Fusillo (Department of Physics, University of Warwick, UK), Detlev Koester (Institute for Theoretical Physics and Astrophysics, University of Kiel, Germany), and Christopher Manser (Department of Physics, University of Warwick, UK).

    See the full article here .


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    ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre EEuropean Extremely Large Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

    ESO/HARPS at La Silla

    ESO 3.6m telescope & HARPS at Cerro LaSilla, Chile, 600 km north of Santiago de Chile at an altitude of 2400 metres.

    MPG/ESO 2.2 meter telescope at Cerro La Silla, Chile, 600 km north of Santiago de Chile at an altitude of 2400 metres

    ESO/Cerro LaSilla, 600 km north of Santiago de Chile at an altitude of 2400 metres.

    ESO VLT at Cerro Paranal in the Atacama Desert, •ANTU (UT1; The Sun ),
    •KUEYEN (UT2; The Moon ),
    •MELIPAL (UT3; The Southern Cross ), and
    •YEPUN (UT4; Venus – as evening star).
    elevation 2,635 m (8,645 ft) from above Credit J.L. Dauvergne & G. Hüdepohl atacama photo,

    2009 ESO VLTI Interferometer image, Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level, •ANTU (UT1; The Sun ),
    •KUEYEN (UT2; The Moon ),
    •MELIPAL (UT3; The Southern Cross ), and
    •YEPUN (UT4; Venus – as evening star).

    ESO VLT 4 lasers on Yepun

    Glistening against the awesome backdrop of the night sky above ESO_s Paranal Observatory, four laser beams project out into the darkness from Unit Telescope 4 UT4 of the VLT.

    ESO/NTT at Cerro La Silla, Chile, at an altitude of 2400 metres

    ESO VLT Survey telescope

    Part of ESO’s Paranal Observatory, the VISTA Telescope observes the brilliantly clear skies above the Atacama Desert of Chile. Credit: ESO/Y. Beletsky, with an elevation of 2,635 metres (8,645 ft) above sea level

    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres

    ESO/E-ELT,to be on top of Cerro Armazones in the Atacama Desert of northern Chile. located at the summit of the mountain at an altitude of 3,060 metres (10,040 ft).

    ESO/APEX high on the Chajnantor plateau in Chile’s Atacama region, at an altitude of over 4,800 m (15,700 ft)

     
  • richardmitnick 5:29 pm on December 3, 2019 Permalink | Reply
    Tags: "New Horizons Confirms Solar Wind Slows Farther from the Sun", Astronomy, , , , , Research could help predict when spacecraft will cross the termination shock, The SWAP instrument aboard NASA's New Horizons spacecraft has confirmed that the solar wind slows as it travels farther from the Sun.   

    NASA From New Horizons: “New Horizons Confirms Solar Wind Slows Farther from the Sun” 

    NASA image

    NASA

    NASA/New Horizons spacecraft

    From New Horizons

    Research could help predict when spacecraft will cross the termination shock

    1
    The SWAP instrument aboard NASA’s New Horizons spacecraft has confirmed that the solar wind slows as it travels farther from the Sun. This schematic of the heliosphere shows the solar wind begins slowing at approximately 4 AU radial distance from the Sun and continues to slow as it moves toward the outer solar system and picks up interstellar material. Current extrapolations reveal the termination shock may currently be closer than found by the Voyager spacecraft. However, increasing solar activity will soon expand the heliosphere and push the termination shock farther out, possibly to the 84-94 AU range encountered by the Voyager spacecraft. (Image credit: Southwest Research Institute; background artist rendering by NASA and Adler Planetarium)

    Measurements taken by the Solar Wind Around Pluto (SWAP) instrument aboard NASA’s New Horizons spacecraft are providing important new insights from some of the farthest reaches of space ever explored. In a paper published recently in The Astrophysical Journal, New Horizons scientists show how the solar wind — the supersonic stream of charged particles blown out by the Sun — evolves at increasing distances from the Sun.

    “Previously, only the Pioneer 10 and 11 and Voyager 1 and 2 missions have explored the outer solar system and outer heliosphere, but now New Horizons is doing that with more modern scientific instruments,” said Heather Elliott, a staff scientist at the Southwest Research Institute, deputy principal investigator of the SWAP instrument and lead author of the paper. “Our Sun’s influence on the space environment extends well beyond the outer planets, and SWAP is showing us new aspects of how that environment changes with distance.”

    The solar wind fills a bubble-like region of space encompassing our solar system, called the heliosphere. From aboard New Horizons, SWAP collects detailed, daily measurements of the solar wind as well as other key components called “interstellar pickup ions” in the outer heliosphere. These interstellar pickup ions are created when neutral material from interstellar space enters the solar system and becomes ionized by light from the Sun or by charge exchange interactions with solar wind ions.

    The journey New Horizons is taking through the outer heliosphere contrasts that of Voyager since this solar cycle is mild compared to the very active solar cycle explored during the Voyager passage through the outer heliosphere. In addition to measuring the solar wind, SWAP is extremely sensitive and simultaneously measures the low fluxes of interstellar pickup ions with unprecedented time resolution and extensive spatial coverage. Currently, New Horizons is the only spacecraft in the solar wind beyond Mars and consequently the only spacecraft measuring the interaction between the solar wind and interstellar material in the outer heliosphere.

    As the solar wind moves farther from the Sun, it encounters an increasing amount of material from interstellar space. When interstellar material is ionized, the solar wind picks up the material and, researchers theorized, slows and heats in response. SWAP has now detected and confirmed this predicted effect.

    The SWAP team compared the New Horizons solar wind speed measurements from 21 to 42 astronomical units to the speeds at 1 AU from both the Advanced Composition Explorer (ACE) and Solar TErrestrial RElations Observatory (STEREO) spacecraft. (One astronomical unit, or AU, is equal to the distance between the Sun and Earth.) By 21 AU, it appeared that SWAP could be detecting the slowing of the solar wind in response to picking up interstellar material. However, when New Horizons traveled beyond Pluto, between 33 and 42 AU, the solar wind measured 6-7% slower than at the 1 AU distance, confirming the effect.

    In addition to confirming the slowing of the solar wind at great distances, the change in the solar wind temperature and density could also provide a means to estimate when New Horizons will join the Voyager spacecraft on the other side of the termination shock, the boundary marking where the solar wind slows to less than the sound speed as it approaches the interstellar medium. Voyager 1 crossed the termination shock in 2004 at 94 AU, followed by Voyager 2 in 2007 at 84 AU. Based on current lower levels of solar activity and lower solar wind pressures, the termination shock is expected to have moved closer to the Sun since the Voyager crossings.

    Extrapolating current trends in the New Horizons measurements also indicates that the termination shock might now be closer than when it was intersected by Voyager. At the earliest, New Horizons will reach the termination shock in the mid-2020s. As the solar cycle activity increases, the increase in pressure will likely expand the heliosphere. This could push the termination shock to the 84-94 AU range found by the Voyager spacecraft before New Horizons has time to reach it.

    “New Horizons has significantly advanced our knowledge of distant planetary objects, and it’s only fitting that it is now also revealing new knowledge about our own Sun and its heliosphere,” said New Horizons Principal Investigator Alan Stern, of SwRI.

    New Horizons is the first mission in NASA’s New Frontiers program. The Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, built and operates the New Horizons spacecraft and manages the mission for NASA’s Science Mission Directorate. SwRI led the payload instrument development and leads the New Horizons science and mission teams from the Tombaugh Science Operations Center located at SwRI facilities in Boulder, Colo. For more information, go to: http://pluto.jhuapl.edu/.

    The paper “Slowing of the Solar Wind in the Outer Heliosphere” by Elliott, D.J. McComas, E.J. Zirnstein, B.M. Randol, P.A. Delamere, G. Livadiotis, F. Bagenal, N.P. Barnes, S.A. Stern, L.A. Young, C.B. Olkin, J. Spencer, H.A. Weaver, K. Ennico, G.R. Gladstone, and C.W. Smith, was published November 11 in The Astrophysical Journal.

    Sorry for the WordPress eeror of repeating material in the right side bar. This is not of my doing. I think it is fixed.

    See the full article here .

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    The New Horizons mission is helping us understand worlds at the edge of our solar system by making the first reconnaissance of the dwarf planet Pluto and by venturing deeper into the distant, mysterious Kuiper Belt – a relic of solar system formation.

    The Journey

    New Horizons launched on Jan. 19, 2006; it swung past Jupiter for a gravity boost and scientific studies in February 2007, and conducted a six-month-long reconnaissance flyby study of Pluto and its moons in summer 2015, culminating with Pluto closest approach on July 14, 2015. As part of an extended mission, pending NASA approval, the spacecraft is expected to head farther into the Kuiper Belt to examine another of the ancient, icy mini-worlds in that vast region, at least a billion miles beyond Neptune’s orbit.

    Sending a spacecraft on this long journey is helping us to answer basic questions about the surface properties, geology, interior makeup and atmospheres on these bodies.

    New Science

    The National Academy of Sciences has ranked the exploration of the Kuiper Belt – including Pluto – of the highest priority for solar system exploration. Generally, New Horizons seeks to understand where Pluto and its moons “fit in” with the other objects in the solar system, such as the inner rocky planets (Earth, Mars, Venus and Mercury) and the outer gas giants (Jupiter, Saturn, Uranus and Neptune).

    Pluto and its largest moon, Charon, belong to a third category known as “ice dwarfs.” They have solid surfaces but, unlike the terrestrial planets, a significant portion of their mass is icy material.

    Using Hubble Space Telescope images, New Horizons team members have discovered four previously unknown moons of Pluto: Nix, Hydra, Styx and Kerberos.

    A close-up look at these worlds from a spacecraft promises to tell an incredible story about the origins and outskirts of our solar system. New Horizons is exploring – for the first time – how ice dwarf planets like Pluto and Kuiper Belt bodies have evolved over time.

    The Need to Explore

    The United States has been the first nation to reach every planet from Mercury to Neptune with a space probe. New Horizons is allowing the U.S. to complete the initial reconnaissance of the solar system.

    A Team Approach

    The Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Maryland, designed, built, and operates the New Horizons spacecraft and manages the mission for NASA’s Science Mission Directorate.
    The National Aeronautics and Space Administration (NASA) is the agency of the United States government that is responsible for the nation’s civilian space program and for aeronautics and aerospace research.

     
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