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  • richardmitnick 12:43 pm on March 21, 2018 Permalink | Reply
    Tags: , astronomy.com, , , , ,   

    From astronomy.com: “The core of the Milky Way unveiled in clearest infrared image yet” 

    Astronomy magazine

    astronomy.com

    February 27, 2018 [Just now in social media.]
    Jake Parks

    1
    This new high-resolution map shows the magnetic field lines embedded in gas and dust around the supermassive black hole (Sagittarius A*) residing in the core of the Milky Way. Red areas show regions where warm dust particles and stars are emitting lots of infrared radiation (heat), while dark blue areas show cooler regions that lack pronounced warm and dusty filaments. E. Lopez-Rodriguez/NASA Ames/University of Texas at San Antonio.

    At the center of nearly every galaxy resides a gargantuan black hole. For the Milky Way, the supermassive black hole — dubbed Sagittarius A* — is so massive that its gravity flings stars around at speeds of up to 18.5 million miles (30 million kilometers) per hour.

    SgrA* NASA/Chandra


    SGR A* , the supermassive black hole at the center of the Milky Way. NASA’s Chandra X-Ray Observatory

    In order to accelerate stars to these breakneck speeds, astronomers estimate that Sagittarius A* must be about 4 million times more massive than the Sun.

    With such a monstrous and intriguing object located in the center of our galaxy, you would think that astronomers know a great deal about it. However, thanks to the fact that the Milky Way is full of light-blocking gas and dust, many questions still remain about the structure and behavior of Sagittarius A*.

    In a paper published last month in the Monthly Notices of the Royal Astronomical Society, astronomers shed a bit of light on this black hole by producing a new high-resolution map that traces the magnetic field lines present within gas and dust swirling around Sagittarius A*. The team created the map, which is the first of its kind, by observing polarized infrared light that is emitted by warm, magnetically aligned dust grains.

    Because infrared light passes straight through the visual-light-blocking dust located between Earth and the Milky Way’s core, astronomers were able to view the area around Sagittarius A* much more clearly than would have been possible with other types of telescopes. Furthermore, since CanariCam combines infrared imaging with a device that preferentially filters polarized light associated with magnetic fields, the team was able to trace the magnetic field lines around Sagittarius A* in unprecedented detail.

    To create the detailed map, which spans about one light-year on each side of Sagittarius A*, the researchers used the CanariCam infrared camera on the Gran Telescopio Canarias (GTC), located on the island of La Palma, Spain. Because infrared light passes straight through the visual-light-blocking dust located between Earth and the Milky Way’s core, astronomers were able to view the area around Sagittarius A* much more clearly than would have been possible with other types of telescopes. Furthermore, since CanariCam combines infrared imaging with a device that preferentially filters polarized light associated with magnetic fields, the team was able to trace the magnetic field lines around Sagittarius A* in unprecedented detail.

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

    “Big telescopes like GTC, and instruments like CanariCam deliver real results,” said Pat Roche, a professor of astrophysics at The University of Oxford, in a press release. “We’re now able to watch material race around a black hole 25,000 light-years away, and for the first time see magnetic fields there in detail.”

    3
    This version of the map shows to what extent the light is polarized at various locations throughout the image. The longer a line is, the more the light is polarized. Sagittarius A*, our galaxy’s supermassive black hole, is located in the center of the image (0,0). Roche et al (MNRAS 2018)

    These new observations not only make for a wonderful image — the clearest infrared image of our galactic core to date — but also provide astronomers with vital information regarding the relationship between luminous stars and the filaments of gas and dust that stretch between them. One prominent feature in the map shows that dusty filaments connect some of the brightest stars in the center of the Milky Way despite incredibly strong stellar winds. The researchers believe that these filaments remain in place because they are bound by magnetic fields that permeate through the dust.

    Based on map, the team also thinks that a smaller magnetic field exists near the core of the Milky Way, and that the field gets stretched out as intervening filaments are pulled apart by gravity. The researchers point out that the filaments, which are several light-years long, seem to pool below (on the map) Sagittarius A*. The team believes that this likely marks a location where streams of gas and dust orbiting the black hole converge.

    Using the CanariCam on GTC, the researchers plan to continue probing the magnetic fields traced in dusty regions throughout our galaxy. Additionally, they hope to continue gathering more detailed observations of the core of the Milky Way to further study the magnetic field around Sagittarius A*. In particular, they would like to determine how the magnetic field interacts with clouds of dust and gas that orbit farther from the black hole, at distances of several light years.

    But for now, we’ll just have to be satisfied with the latest piece of the puzzle.

    [The work of Andrea Ghez deserves credit here.

    Andrea Mia Ghez is an American astronomer and professor in the Department of Physics and Astronomy at UCLA. In 2004, Discover magazine listed Ghez as one of the top 20 scientists in the United States who have shown a high degree of understanding in their respective fields. Ghez is a member of the UCLA Galactic Center Group

    Andrea Ghez, UCLA

    Andrea’s Favorite star SO-2

    Her current research involves using high spatial resolution imaging techniques, such as the adaptive optics system at the Keck telescopes, to study star-forming regions and the supermassive black hole at the center of the Milky Way known as Sagittarius A*. She uses the kinematics of stars near the center of the Milky Way as a probe to investigate this region. The high resolution of the Keck telescopes gave a significant improvement over the first major study of galactic center kinematics by Reinhard Genzel’s group.


    Keck Observatory, Maunakea, Hawaii, USA.4,207 m (13,802 ft), above sea level, showing also NASA’s IRTF and NAOJ Subaru

    In 2004, Ghez was elected to the National Academy of Sciences. She has appeared in a long list of notable media presentations. The documentaries have been produced by organizations such as BBC, Discovery Channel, and The History Channel; in 2006 there was a presentation on Nova. She was identified as a Science Hero by The My Hero Project.]

    See the full article here .

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  • richardmitnick 1:46 pm on October 13, 2017 Permalink | Reply
    Tags: Astronomers spot one of the brightest novae ever, , astronomy.com, , ,   

    From astronomy.com: “Astronomers spot one of the brightest novae ever” 

    Astronomy magazine

    astronomy.com

    October 11, 2017
    Alison Klesman

    These new stars aren’t new at all — but they still have a story to tell.

    1
    Last year, one of the brightest novae ever spotted (right) went off in the Small Magellanic Cloud. The area prior to the nova (left) appears unremarkable. OGLE survey

    Novae occur when a dead star flares back to life in the sky. These events signal a white dwarf, the remnant of a star like our Sun, suddenly and briefly reigniting fusion in its thin atmosphere as it pulls mass from a companion star in a binary system. The event is called a nova because people once thought they were completely new stars in the sky. Now we know they’re not, but these transient phenomena are just as astronomically intriguing, giving us a glimpse at the dynamic interactions in binary star systems. And recently, astronomers just spotted one of the brightest yet.

    The new “star” (or, in truth, the recent flare-up of a long-dead star) occurred in the Small Magellanic Cloud (SMC), a dwarf galaxy gravitationally bound to our larger Milky Way.

    Small Magellanic Cloud. NASA/ESA Hubble and ESO/Digitized Sky Survey 2

    The SMC lies 200,000 light-years away and is visible from the Southern Hemisphere. Ground-based telescopes including instruments at the South African Astronomical Observatory, the Las Cumbres Observatory, the Las Campanas Observatory, and the Cerro Tololo Inter-American Observatory caught the event in conjunction with NASA’s orbiting Swift Gamma-Ray Burst Mission.

    1
    South African Astronomical Observatory, located in Sutherland, which is 370 kilometres (230 mi) from Observatory, Cape Town, where the headquarters is located.

    LCOGT Las Cumbres Observatory Global Telescope Network, Haleakala Hawaii, USA

    CTIO Cerro Tololo Inter-American Observatory, CTIO Cerro Tololo Inter-American Observatory,approximately 80 km to the East of La Serena, Chile, at an altitude of 2200 meters

    NASA/SWIFT Telescope

    SMCN 2016-10a, the nova’s designation, was spotted in October 2016. A paper aptly titled Multiwavelength observations of nova SMCN 2016-10a – Probably the brightest nova in the SMC and one of the brightest on record, has been accepted for publication in Monthly Notices of the Royal Astronomical Society. First author Elias Aydi is jointly affiliated with the South African Astronomical Observatory and the University of Cape Town.

    The work outlines comprehensive observations of the nova — as advertised, the brightest ever seen in the SMC or any other galaxy not the Milky Way — from multiple observatories using numerous instruments. The data, which includes details on the white dwarf’s composition, temperature, magnetic field, and brightness over time, gives astronomers a treasure trove of data to work with. “The present observations provide the kind of coverage in time and spectral color that is needed to make progress for gaining understanding of a nova in a neighboring galaxy,” said Paul Kuin of the Mullard Space Science Laboratory, University College London, a collaborator on the work, in a press release. “Observing the nova in different wavelengths using world-class telescopes such as Swift and the Southern African Large Telescope help us reveal the condition of matter in nova ejecta as if it were nearby.”

    SALT South African Large Telescope, at the South African Astronomical Observatory, located in Sutherland, which is 370 kilometres (230 mi) from Observatory, Cape Town, where the headquarters is located

    2
    Novae occur when a white dwarf pulls enough matter off a companion star to ignite a runaway fusion reaction in its atmosphere. These flares, while bright, don’t destroy the white dwarf, as a supernova would. Casey Reed/NASA

    That close-up view has shown scientists that the nova’s progenitor white dwarf “is close to the theoretical maximum,” said Kim Page, who led the X-ray analysis of Swift’s data from the University of Leicester. That maximum, called the Chandrasekhar limit, states that if a white dwarf becomes more massive than about 1.4 times the mass of our Sun, it will tear itself apart. Based on their current mass estimate for SMCN 2016-10a’s white dwarf, “continued accretion might cause it eventually to be totally destroyed in a supernova explosion,” said Page.

    Despite its distance, the nova’s brightness makes it a valuable contributor to astronomers’ efforts to understand such events, including how and why they occur. Not all novae are the same — some flare quickly, others more slowly. Some novae repeat fairly regularly, while others have not been seen to reoccur (within record, at least). Understanding the physics behind these events will let astronomers delve deeper into the workings of stars and their life cycles. Given that this white dwarf also seems poised to someday go supernova, it’s providing astronomers with a unique view of the events that may lead up to a white dwarf’s ultimate demise.

    See the full article here .

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  • richardmitnick 4:55 pm on March 31, 2017 Permalink | Reply
    Tags: , astronomy.com, ,   

    From Astronomy: “Rethinking the habitable zone” 

    Astronomy magazine

    Astronomy Magazine

    March 28, 2017
    K.N. Smith

    1
    NASA

    With proof of liquid water in the farthest reaches of the solar system, it’s clear that the habitable zone isn’t the only place life might exist, but it may be years before that knowledge changes how — and where — astrobiologists look for habitable exoplanets.

    If you want to look for life in space, most astronomy textbooks will tell you to stick to the Goldilocks Zone: the region around a star that’s the right temperature range for liquid water to exist on the surface of a planet, also called the habitable zone. The trouble is that water seems to be everywhere on icy moons in the outer solar system, well beyond the textbook habitable zone, and some planetary scientists have even suggested that there could be liquid seas out in the Kuiper Belt. Thanks to those discoveries, some experts are suggesting that it could be time to rethink how we define the habitable zone. But does that mean changing how we search for potentially habitable worlds in other solar systems?

    2
    Wilfried Bauer

    Beyond the Goldilocks Zone

    Until the last few decades, scientists assumed that the conditions for life, starting with liquid water, could only exist in a planetary neighborhood exactly like ours.

    “It’s been a big shift, but it’s been kind of gradual; it just kind of kept creeping up on people,” JPL’s Diana Blaney, principal investigator on the Mapping Imaging Spectrometer for Europa, said.

    9
    Prototype MISE spectrometer

    That shift happened in two parts, fueled by discoveries in broadly different fields. First came the idea that life could live in colder, darker, stranger places than biologists could have dreamed. Second came the idea that the most basic conditions for survival – chiefly the presence of liquid water – could turn up in unexpected places.

    Most of the liquid water we’ve found in the solar system is concealed beneath the icy crusts of moons orbiting Jupiter and Saturn, but before scientists sent Voyager, Galileo, and Cassini out into the outer solar system to find those sub-surface oceans, they found analogues here on Earth. In 1970, airborne radio-echo sounding surveys found the first evidence of lakes hidden beneath several kilometers of glacial ice in Antarctica. Researchers have found 379 such lakes so far, and a series of discoveries in the last few years have confirmed the presence of microbial life beneath several of them.

    Just before the first mission to the outer solar system, in 1976 – while Viking 1 was searching for life on Mars – botanists discovered bacteria eking out a living in porous sandstone in the cold, dry, thoroughly inhospitable mountains of Antarctica’s Ross Desert. The following year, in 1977, a marine geology expedition discovered hydrothermal vents in the Galapagos Rift, deep beneath the eastern Pacific Ocean. In the lightless depths of the ocean, they found a thriving ecosystem based on chemosynthesis.

    Looking back, it’s easy to see how discoveries of extremophiles and sub-glacial lakes here on Earth pointed toward the idea that wildly unexpected environments out there might be habitable.

    The Voyager spacecraft launched later that year, on their way to the outer solar system; it was a mission that some in the scientific community at the time didn’t expect much from – after all, the moons of the outer solar system were far outside the bounds of the Goldilocks Zone.


    NASA/Voyager 1

    “It was really Voyager that broke all of this open, because a lot of scientists thought that most of the outer solar system was just dead balls of ice and rock,” said planetary scientist Jonathan Lunine of Cornell University. From 1979 to 1981, Voyager sent home images of active, complex worlds: Io with its violent, volcanic surface; Titan with its thick, hazy atmosphere; and Europa with a cracked crust that hinted at tidal movements of an ocean beneath.

    Once scientists realized that the moons of the outer solar system were dynamic, unexpectedly complex worlds, some began to speculate that they could host life, warmed not just by the light of the Sun, but by the tidal pull of a gas giant. Meanwhile, discoveries here on Earth continued apace, feeding into astrobiologists’ ideas about where life might flourish.

    4
    NASA Goddard/Katrina Jackson

    All these worlds are yours …

    The Galileo spacecraft left Earth in 1989, bound for Jupiter amid intensifying speculation about what it might find waiting beneath the ice at Europa.


    ESA Galileo Spacecraft

    Galileo’s close flybys of the Jovian moons confirmed what Voyager’s images had hinted at: liquid water exists well outside the familiar confines of the Goldilocks Zone, beneath the ice of Europa and Ganymede. Then, in 2005, the Cassini spacecraft captured surprising images of watery plumes jetting out from the southern surface of Enceladus.


    NASA/ESA/ASI Cassini Spacecraft

    As the data came back from Galileo and Cassini, it collided with research on extremophiles here on Earth, fueling discussions about which unexpected corners of our solar system might turn out to be habitable.

    “I think they actually reinforced each other, you know?” said Blaney. “A lot of the stuff, I think, was happening in parallel. You were sitting in [science conferences] listening to people talk about the building evidence for an ocean on Europa, and then you would go next door and listen to someone talk about life in the Antarctic dry valleys, and that kind of cross-communication between the different communities, I think, got people thinking more about Europa potentially having life now.”

    Now astrobiologists may have to rethink the limits of habitability again. In late 2016, William McKinnon, a planetary scientist at Washington University in St. Louis, and his colleagues concluded that orientation of Sputnik Planitia, the icy heart-shaped basin in Pluto’s northern hemisphere, could only be explained by an uneven distribution of mass in the planet’s crust.

    10
    Original discription: This image contains the initial, informal names being used by the New Horizons team for the features on Pluto’s Sputnik Planum (plain). Names were selected based on the input the team received from the Our Pluto naming campaign. Names have not yet been approved by the International Astronomical Union (IAU).
    Date 29 July 2015
    Source http://pluto.jhuapl.edu/Multimedia/Images/index.php
    Author JPL/NASA

    That, in turn, the researchers claimed, could only be explained by a liquid ocean of (mostly) water beneath the ice. There’s no proof yet that Pluto hosts a subglacial lake similar to those beneath Antarctica’s ice, but the research proves it’s theoretically possible for Kuiper Belt Objects to hold liquid water.

    “We know oceans exist beneath icy crusts, generally maintained by tidal heating (Europa and Enceladus). What Pluto does is to push the potential limits of habitable zones to icy dwarf planets in deep solar space,” said McKinnon.

    6
    NASA / JHUAPL / SwRI

    Miniature Habitable Zones

    The current view among many astrobiologists is that, because there are so many environments where liquid water – and therefore the basic ingredients for life – might exist, there are many habitable zones in a solar system. There’s the traditional Goldilocks Zone, where solar heating keeps the planet at just the right temperature; there are orbits around gas giants, where tidal heating could keep water liquid and potentially habitable beneath the ice.

    “The data point I seize on is more the number of potential habitable environments we have in our single solar system. I don’t think that’s a fluke,” said Curt Niebur, program scientist for NASA’s Europa Multiple Flyby Mission. “I think as we peer outward, we are going to find that in most solar systems we explore, either in person or via telescopes, that there is likely to be multiple habitable zones in every solar system.”

    In fact, we’ve found more liquid water on icy moons in the outer solar system than in the temperate belt of the Habitable Zone. Some planetary scientists are even beginning to talk about the idea that gas giants, like Jupiter and Saturn, create their own habitable zones through their tidal heating of icy moons like Europa and Enceladus. And if McKinnon and his colleagues turn out to be right about what lies beneath Pluto’s Sputnik Planum, then there may even be little habitable zones far out in the frozen reaches of the Kuiper Belt.

    “Sometimes it’s around giant planets like Jupiter, sometimes it’s on Earth-like planets, sometimes it’s in the deep solar system like at Pluto,” said Niebur. “I think every one of those three cases is a Goldilocks zone, and I think that there are more Goldilocks zones out there remaining to be discovered.”

    That means that we may not be giving gas giants enough credit as hosts for potentially habitable worlds. For one thing, they seem to be much more common – or at least easier to detect from Earth – than rocky planets, especially rocky planets that happen to orbit just the right distance from their stars, which means the odds are in favor of a gas giant winning the lottery of biochemistry.

    “I think it’s probably likely that gas giants are more common than terrestrial worlds, so just by sheer numbers, I think that they could either directly or indirectly provide far more habitable zones, far more Goldilocks zones, than terrestrial planets,” said Niebur.

    That’s an eye-opening concept for astrobiology, but in practice it could be nearly impossible to draw a neat map of that type of habitable zone. Mapping a star’s Goldilocks Zone is pretty straightforward; the temperature of a planet depends on its distance from the star, as well as how much heat the star produces. Figuring out the region of potential habitability around a gas giant, on the other hand, requires a lot more information about the gas giant, its moons, and how they all interact.

    The oceans of Europa, Enceladus, and Ganymede rely on tidal heating to keep them liquid, and those tidal forces come not only from the gravitational pull of the gas giants, but from gravitational interactions with other moons. For instance, every time Ganymede orbits Jupiter, Europa makes exactly two orbits, and Io makes exactly four. That means that the planets line up regularly, giving each other a gravitational tug that stretches their orbits out, making them more elliptical.

    Thanks to orbital resonance, the tidal effects of the planet’s gravity are much more pronounced. In simple terms, that’s because the difference between “high tide” and “low tide” is exaggerated. That, in turn, keeps the moons’ interiors in motion – and warm.

    That’s why Io is such a hotbed of volcanic activity, and it’s why Europa and Ganymede have enough geothermal heat to maintain liquid water so far from the Goldilocks Zone. Around Saturn, Enceladus is in a similar orbital resonance with its sister moon Dione, and that’s what keeps the plumes erupting from cracks in the moon’s icy crust.

    Astronomers have a very good understanding of the dynamics that make the moons of Jupiter and Saturn so active, but beyond our solar system, there’s no way to spot tidally heated habitable zones – yet. To predict whether a moon might experience enough tidal heating to keep water liquid in its interior, astronomers would need to know how many other moons were orbiting the same planet and whether those orbits are in resonance with each other.
    “The broader definition of habitable zones will also include some that we just can’t observe with the missions that we’re anticipating in the next decades,” said Lunine. “That includes icy moons around gas giants, which may be harboring life, or at least habitable oceans, that we can’t see yet.”

    7
    Danielle Futselaar / Franck Marchis / SETI Institute.

    Observable Habitable Zones

    It’s fascinating to think that an interesting new gas giant in a solar system like 51 Eridani may play host to another Enceladus or Europa, but with our current technology, those potentially habitable icy exo-moons are still invisible to astronomers here on Earth.

    “The problem, of course, is that if you really have something the size of Enceladus or even Europa orbiting around a giant planet, around another star, you have a really tough time observing it, and if it’s habitable five or ten kilometers below the surface, you’re sort of out of luck,” said Lunine. “It would be a very, very difficult challenge to make the kinds of observations of a Europa or an Enceladus that are required to determine its habitability.”

    Of course, that kind of observation is feasible for icy moons in our own solar system, because we can send probes to fly through the plumes of Enceladus or perhaps one day land on the surface of Europa, but to study objects in other solar systems, astronomers have to stick with looking for spectra through a telescope. So even if there might be miniature habitable zones in the other reaches of most solar systems, Earthbound astrobiologists can only speculate.

    Instead, Lunine says that in the search for potentially habitable exoplanets, what really matters is something he calls the observable habitable zone: the area where water might exist, and in a place where we could see evidence of it with a telescope. That means a planet that telescopes can actually observe, and it means liquid water existing stably on the surface, not hidden beneath a layer of ice. Essentially, it means the traditional Goldilocks Zone.

    “The technology limitations mean that you’re going to have to restrict yourself to the traditional definition of the Goldilocks, but I think that as our technology increases, we can pursue the more modern and accurate Goldilocks zone concept as well,” said Niebur.

    In the future, that might change. In the meantime, it’s worth keeping in mind that the search for habitable worlds probably still has surprises in store.

    “People have to kind of keep an open mind about what’s possible and – and let the data take you where it takes you, because sometimes it takes you to places that are unexpected – like Europa,” said Blaney.

    See the full article here .

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  • richardmitnick 10:18 am on September 27, 2016 Permalink | Reply
    Tags: , astronomy.com, , , Rossiter-McLaughlin effect,   

    From astronomy.com: “Sun spots may be tricking scientists” 

    Astronomy magazine

    astronomy.com

    September 27, 2016
    Shannon Stirone

    1
    Illustration of the Rossiter-McLaughlin effect. Ricardo Cardoso Reis(IA/UPorto)

    For millennia scientists and observers have learned from our Sun and other stars that move throughout the night sky. The life and death of stars teaches us about star formation, solar system formation and occasionally fills on those odds and ends questions about how we came to be. Depending on what they’re searching for, stars like our Sun can help modern day scientists discover other planetary bodies, like exoplanets. One of the main ways they do this is by using telescopes like Kepler that looks for a dimming of the light curve as a planet transits across the plane of the star.

    Planet transit. NASA/Ames
    Planet transit. NASA/Ames

    The bane of exoplanet hunter’s existence is the sunspot. Our sun goes through cycles and sunspots can easily be seen with a solar telescope of even solar eclipse glasses. But a sunspot can be there one day, and gone the next. If a telescope like Kepler is examining a star looking for planets and a sunspot is present on the surface that will affect the amount of photons hitting its spectrometer, and could lead to false positives.

    However, understanding these strange planetary bodies from these extreme distances can prove challenging. Recently researches at the University of Porto in Portugal and Institute of Astrophysics of Georg-August-University of Göttingen published a paper in the journal of Astronomy and Astrophysics showing that the normal activity of stars could be the reason why some exoplanet angles appear extremely misaligned.

    Using the Rossiter-McLaughlin effect, or RM effect, exoplanet researchers measure the spin-orbit tilt of exoplanets, which is a factor in determining a specific planetary migration model. They want to know if the planet formed cleanly inside the planetary nebula, or migrated inward after forming in the outer reaches, accounting for a discombobulated arrangement.

    The RM effect measures the amount of doppler effected light coming from the star. Using spectroscopic wavelengths of light they measure the amount of red and blue photons coming from the host star. If looking head on at a star like our Sun, it will spin in one direction — if it spins in a clockwise motion, the right side of the star will look slightly red-shifted as it moves away from us and the side spinning towards us will look slightly more blue-shifted. When a planet passes in front of its star, it will block out either more red or blue light, depending on its size and the angle in which it’s orbiting.

    Planet formation is a tricky business and it can happen in a myriad of ways. Many planets orbit at a relatively normal angle, but some can be tilted a full 90 degrees, or pole-on as they orbit their star. These extreme tilts tell scientists a lot about how these planets formed, and how their host solar system formed.

    “This angle is very important because it is a window into the past,” says co-author Pedro Figueira from the University of Porto. “It lets us know if the planet is likely to have been formed in a disk and migrated in smoothly through gravitational interaction, or formed violently around other planets or stars. In the first case we have a small misalignment angle, in the second one a large one.”

    One of the biggest issues scientists have when searching for these exoplanets is stellar activity of the planet’s host star. As we know from our Sun, stars can be quite active, creating sunspots, ejecting plasma out into space, and displaying brighter spots on the surface called “plages” which are convecting areas that appear to be red-shifting as the material moves deeper into the star. All of these normal stellar behaviors interfere with the amount of red and blue light reaching the observer, and in turn can interfere with the spectra data being collected from the telescope.

    One way around this is to study the stars of interests for months or even years to predict their surface patterns. “This study is a part of a growing body of work pointing to how crucial the understanding of solar activity is when it comes to interpreting exoplanet results,” says Dr. Sarah Ballard, exoplanetary researcher at MIT. “It has a context of a growing movement within exoplanet research of how stellar activity bears upon radial velocity observations, transits and RM measurements.”

    The team hopes that their findings will inform future research and how instruments are designed on upcoming observatories. “These results will make us rethink a bit the way we derive these angles, and will be more conservative on the errors assigned to each spinning angle,” says Figueira.While this likely won’t negate any previous results, it could help explain the anomalies that still exist in the catalog of wonky exoplanets and hopefully help scientists better understand how they form in the first place.

    See the full article here .

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