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  • richardmitnick 11:06 am on May 26, 2020 Permalink | Reply
    Tags: , , , , Carnegie Institution For Science,   

    From Carnegie Institution for Science: “‘Elegant’ solution reveals how the universe got its structure” 

    Carnegie Institution for Science
    From Carnegie Institution for Science

    April 27, 2020

    The universe is full of billions of galaxies—but their distribution across space is far from uniform. Why do we see so much structure in the universe today and how did it all form and grow?

    A 10-year survey of tens of thousands of galaxies made using the Magellan Baade Telescope at Carnegie’s Las Campanas Observatory in Chile [below] provided a new approach to answering this fundamental mystery. The results, led by Carnegie’s Daniel Kelson, are published in Monthly Notices of the Royal Astronomical Society.

    1
    Why is the distribution of structure in the cosmos not uniform? The universe’s first structure originated when some of the material flung outward by the Big Bang overcame its trajectory and collapsed on itself, forming clumps. A team of Carnegie researchers showed that denser clumps of matter grew faster, and less-dense clumps grew more slowly. The group’s data revealed the distribution of density in the universe over the last 9 billion years. (On the illustration, violet represents low-density regions and red represents high-density regions.) Working backward in time, their findings reveal the density fluctuations (far right, in purple and blue) that created the universe’s earliest structure. This aligns with what we know about the ancient universe from the afterglow of the Big Bang, called the Cosmic Microwave Background (far right in yellow and green). The researchers achieved their results by surveying the distances and masses of nearly 100,000 galaxies, going back to a time when the universe was only 4.5 billion years old. About 35,000 of the galaxies studied by the Carnegie-Spitzer-IMACS Redshift Survey are represented here as small spheres. The illustration is courtesy of Daniel Kelson. CMB data is based on observations obtained with Planck, an ESA science mission with instruments and contributions directly funded by ESA Member States, NASA, and Canada.

    “How do you describe the indescribable?” asks Kelson. “By taking an entirely new approach to the problem.”

    “Our tactic provides new—and intuitive—insights into how gravity drove the growth of structure from the universe’s earliest times,” said co-author Andrew Benson. “This is a direct, observation-based test of one of the pillars of cosmology.”

    The Carnegie-Spitzer-IMACS Redshift Survey was designed to study the relationship between galaxy growth and the surrounding environment over the last 9 billion years, when modern galaxies’ appearances were defined.

    The first galaxies were formed a few hundred million years after the Big Bang, which started the universe as a hot, murky soup of extremely energetic particles. As this material expanded outward from the initial explosion, it cooled, and the particles coalesced into neutral hydrogen gas. Some patches were denser than others and, eventually, their gravity overcame the universe’s outward trajectory and the material collapsed inward, forming the first clumps of structure in the cosmos.

    The density differences that allowed for structures both large and small to form in some places and not in others have been a longstanding topic of fascination. But until now, astronomers’ abilities to model how structure grew in the universe over the last 13 billion years faced mathematical limitations.

    “The gravitational interactions occurring between all the particles in the universe are too complex to explain with simple mathematics,” Benson said.

    So, astronomers either used mathematical approximations—which compromised the accuracy of their models—or large computer simulations that numerically model all the interactions between galaxies, but not all the interactions occurring between all of the particles, which was considered too complicated.

    “A key goal of our survey was to count up the mass present in stars found in an enormous selection of distant galaxies and then use this information to formulate a new approach to understanding how structure formed in the universe,” Kelson explained.

    The research team—which also included Carnegie’s Louis Abramson, Shannon Patel, Stephen Shectman, Alan Dressler, Patrick McCarthy, and John S. Mulchaey, as well as Rik Williams , now of Uber Technologies—demonstrated for the first time that the growth of individual proto-structures can be calculated and then averaged over all of space.

    Doing this revealed that denser clumps grew faster, and less-dense clumps grew more slowly.

    They were then able to work backward and determine the original distributions and growth rates of the fluctuations in density, which would eventually become the large-scale structures that determined the distributions of galaxies we see today.

    In essence, their work provided a simple, yet accurate, description of why and how density fluctuations grow the way they do in the real universe, as well as in the computational-based work that underpins our understanding of the universe’s infancy.

    “And it’s just so simple, with a real elegance to it,” added Kelson.

    The findings would not have been possible without the allocation of an extraordinary number of observing nights at Las Campanas.

    “Many institutions wouldn’t have had the capacity to take on a project of this scope on their own,” said Observatories Director John Mulchaey. “But thanks to our Magellan Telescopes, we were able to execute this survey and create this novel approach to answering a classic question.”

    “While there’s no doubt that this project required the resources of an institution like Carnegie, our work also could not have happened without the tremendous number of additional infrared images that we were able to obtain at Kitt Peak and Cerro Tololo, which are both part of the NSF’s National Optical-Infrared Astronomy Research Laboratory,” Kelson added.

    Kitt Peak National Observatory of the Quinlan Mountains in the Arizona-Sonoran Desert on the Tohono O’odham Nation, 88 kilometers 55 mi west-southwest of Tucson, Arizona, Altitude 2,096 m (6,877 ft)

    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

    See the full article here .


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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Carnegie Institution of Washington Bldg

    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.

    Carnegie 6.5 meter Magellan Baade and Clay Telescopes located at Carnegie’s Las Campanas Observatory, Chile. over 2,500 m (8,200 ft) high


    6.5 meter Magellan Telescopes located at Carnegie’s Las Campanas Observatory, Chile


    Carnegie Las Campanas 2.5 meter Irénée Dupont telescope, Atacama Desert, over 2,500 m (8,200 ft) high approximately 100 kilometres (62 mi) northeast of the city of La Serena,Chile


    Carnegie Institution Swope telescope at Las Campanas, Chile, 100 kilometres (62 mi) northeast of the city of La Serena. near the north end of a 7 km (4.3 mi) long mountain ridge. Cerro Las Campanas, near the southern end and over 2,500 m (8,200 ft) high, at Las Campanas, Chile

     
  • richardmitnick 3:47 pm on April 27, 2020 Permalink | Reply
    Tags: , , , , Carnegie Institution For Science,   

    From Carnegie Institution for Science: “‘Elegant’ solution reveals how the universe got its structure” 

    Carnegie Institution for Science
    From Carnegie Institution for Science

    The universe is full of billions of galaxies—but their distribution across space is far from uniform. Why do we see so much structure in the universe today and how did it all form and grow?

    Universe map Sloan Digital Sky Survey (SDSS) 2dF Galaxy Redshift Survey

    A 10-year survey of tens of thousands of galaxies made using the Magellan Baade Telescope at Carnegie’s Las Campanas Observatory in Chile provided a new approach to answering this fundamental mystery. The results, led by Carnegie’s Daniel Kelson, are published in Monthly Notices of the Royal Astronomical Society.

    “How do you describe the indescribable?” asks Kelson. “By taking an entirely new approach to the problem.”

    “Our tactic provides new—and intuitive—insights into how gravity drove the growth of structure from the universe’s earliest times,” said co-author Andrew Benson. “This is a direct, observation-based test of one of the pillars of cosmology.”

    The Carnegie-Spitzer-IMACS Redshift Survey was designed to study the relationship between galaxy growth and the surrounding environment over the last 9 billion years, when modern galaxies’ appearances were defined.

    The first galaxies were formed a few hundred million years after the Big Bang, which started the universe as a hot, murky soup of extremely energetic particles. As this material expanded outward from the initial explosion, it cooled, and the particles coalesced into neutral hydrogen gas. Some patches were denser than others and, eventually, their gravity overcame the universe’s outward trajectory and the material collapsed inward, forming the first clumps of structure in the cosmos.

    CMB per ESA/Planck

    The density differences that allowed for structures both large and small to form in some places and not in others have been a longstanding topic of fascination. But until now, astronomers’ abilities to model how structure grew in the universe over the last 13 billion years faced mathematical limitations.

    “The gravitational interactions occurring between all the particles in the universe are too complex to explain with simple mathematics,” Benson said.

    So, astronomers either used mathematical approximations—which compromised the accuracy of their models—or large computer simulations that numerically model all the interactions between galaxies, but not all the interactions occurring between all of the particles, which was considered too complicated.

    “A key goal of our survey was to count up the mass present in stars found in an enormous selection of distant galaxies and then use this information to formulate a new approach to understanding how structure formed in the universe,” Kelson explained.

    The research team—which also included Carnegie’s Louis Abramson, Shannon Patel, Stephen Shectman, Alan Dressler, Patrick McCarthy, and John S. Mulchaey, as well as Rik Williams , now of Uber Technologies—demonstrated for the first time that the growth of individual proto-structures can be calculated and then averaged over all of space.

    Doing this revealed that denser clumps grew faster, and less-dense clumps grew more slowly.

    They were then able to work backward and determine the original distributions and growth rates of the fluctuations in density, which would eventually become the large-scale structures that determined the distributions of galaxies we see today.

    In essence, their work provided a simple, yet accurate, description of why and how density fluctuations grow the way they do in the real universe, as well as in the computational-based work that underpins our understanding of the universe’s infancy.

    “And it’s just so simple, with a real elegance to it,” added Kelson.

    The findings would not have been possible without the allocation of an extraordinary number of observing nights at Las Campanas.

    “Many institutions wouldn’t have had the capacity to take on a project of this scope on their own,” said Observatories Director John Mulchaey. “But thanks to our Magellan Telescopes, we were able to execute this survey and create this novel approach to answering a classic question.”

    Carnegie 6.5 meter Magellan Baade and Clay Telescopes located at Carnegie’s Las Campanas Observatory, Chile. over 2,500 m (8,200 ft) high

    “While there’s no doubt that this project required the resources of an institution like Carnegie, our work also could not have happened without the tremendous number of additional infrared images that we were able to obtain at Kitt Peak and Cerro Tololo, which are both part of the NSF’s National Optical-Infrared Astronomy Research Laboratory,” Kelson added.

    Kitt Peak National Observatory of the Quinlan Mountains in the Arizona-Sonoran Desert on the Tohono O’odham Nation, 88 kilometers 55 mi west-southwest of Tucson, Arizona, Altitude 2,096 m (6,877 ft)

    CTIO an astronomical observatory located on Cerro Tololo in the Coquimbo Region of northern Chile, with additional facilities located on Cerro Pachón about 10 kilometres (6.2 mi) to the southeast. Altitude 2,207 m (7,241 ft)

    See the full article here .


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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Carnegie Institution of Washington Bldg

    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.

    Carnegie 6.5 meter Magellan Baade and Clay Telescopes located at Carnegie’s Las Campanas Observatory, Chile. over 2,500 m (8,200 ft) high


    6.5 meter Magellan Telescopes located at Carnegie’s Las Campanas Observatory, Chile


    Carnegie Las Campanas 2.5 meter Irénée Dupont telescope, Atacama Desert, over 2,500 m (8,200 ft) high approximately 100 kilometres (62 mi) northeast of the city of La Serena,Chile


    Carnegie Institution Swope telescope at Las Campanas, Chile, 100 kilometres (62 mi) northeast of the city of La Serena. near the north end of a 7 km (4.3 mi) long mountain ridge. Cerro Las Campanas, near the southern end and over 2,500 m (8,200 ft) high, at Las Campanas, Chile

     
  • richardmitnick 12:16 pm on March 11, 2020 Permalink | Reply
    Tags: A very young planet called DS Tuc Ab, , , , Carnegie Institution For Science,   

    From Carnegie Institution for Science: “New technique could elucidate earliest stages of planet’s life” 

    Carnegie Institution for Science
    From Carnegie Institution for Science

    March 09, 2020

    A new kind of astronomical observation helped reveal the possible evolutionary history of a baby Neptune-like exoplanet.

    1
    DS Tuc AB by M Weiss, CfA.

    2
    Animation courtesy of George Zhou, CfA.

    To study a very young planet called DS Tuc Ab, a Harvard & Smithsonian Center for Astrophysics-led team that included six Carnegie astronomers—Johanna Teske, Sharon Wang, Stephen Shectman, Paul Butler, Jeff Crane, and Ian Thompson—developed a new observational modeling tool. Their work will be published in The Astrophysical Journal Letters and represents the first time the orbital tilt of a planet younger than 45 million years—or about 1/100th the age of the Solar System—has been measured.

    “A lot of things can happen between when a planet is formed and when we see them,” said lead author George Zhou of the CfA. “The vast majority of planets we find are already mature and we don’t know what they were like when they were young.”

    DS Tuc Ab is a hot Neptune, which orbits one star in a two-star system on a short, eight-day period in a relatively flat plane.

    “DS Tuc Ab is at an interesting age,” because the rotating disk of gas and dust from which it formed around its host star has dissipated, explained Ben Montet of the University of New South Wales, who was the lead author of a companion paper on which the Carnegie group were also co-authors that was published in The Astronomical Journal and used a different technique to study the planet. “We can see the planet, but we thought it was still too young for the orbit of other distant stars to manipulate its path.”

    DS Tuc Ab was discovered in 2019 by Dartmouth’s Elisabeth Newton and her team using data from NASA’s TESS Mission. A parallel discovery paper was published the same year by scientists the National Institute for Astrophysics in Italy.

    Soon after, researchers began observing the planet using the Planet Finder Spectrograph on the Magellan Clay Telescope at Carnegie’s Las Campanas Observatory in Chile. Their goal was to determine whether the newly formed planet had experienced some chaotic dynamical interactions in its past. Astronomers often find planets around other stars in orbits wildly different to the planets in our own Solar System. Some have been found in polar, and even retrograde orbits, because of tugs from outer planets.

    Carnegie Planet Finder Spectrograph on the Magellan II Clay telescope at Las Campanas, Chile, altitude over 2,500 m (8,200 ft) high

    Carnegie Insitution II Telescope, Clay, in the southern Atacama Desert of Chile approximately 100 kilometres (62 mi) northeast of the city of La Serena,near the southern end and over 2,500 m (8,200 ft) high.

    To answer this question, the researchers observed DS Tuc Ab as it passed in front of its host star to measure the effect that the planet had on the starlight. If the planet blocked an equal amount of light as it passed across the surface of the star, for example, this would indicate a well-aligned orbit.

    However, an abundance of stellar spots on DS Tuc Ab’s host star made this measurement very difficult. To combat these challenges and characterize the planet and star system, scientists developed their new technique to track the young planet in its orbit. They accomplished this by simultaneously modeling how the planet blocked light across the stellar surface and how the star’s cool spots changed the intrinsic light it was emitting.

    “Going forward, this system will allow astronomers to develop a better understanding of planets in their infancy,” said Teske. “We’re especially interested in how ‘hot Neptunes’ move or form so close to their host stars.”

    This has been a longstanding astronomical mystery that DS Tuc Ab might be perfectly positioned to help solve. Its youth means it probably didn’t form farther out and get kicked closer to its host by a collision or other external force. But its relatively flat orbital tilt indicate that it wasn’t pulled into this position by interaction with its host star’s companion, either.

    “This is a very special system that could teach us so much about the earliest stages of how planetary systems evolve,” Teske added.

    See the full article here .


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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Carnegie Institution of Washington Bldg

    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.

    Carnegie 6.5 meter Magellan Baade and Clay Telescopes located at Carnegie’s Las Campanas Observatory, Chile. over 2,500 m (8,200 ft) high


    6.5 meter Magellan Telescopes located at Carnegie’s Las Campanas Observatory, Chile


    Carnegie Las Campanas 2.5 meter Irénée Dupont telescope, Atacama Desert, over 2,500 m (8,200 ft) high approximately 100 kilometres (62 mi) northeast of the city of La Serena,Chile


    Carnegie Institution Swope telescope at Las Campanas, Chile, 100 kilometres (62 mi) northeast of the city of La Serena. near the north end of a 7 km (4.3 mi) long mountain ridge. Cerro Las Campanas, near the southern end and over 2,500 m (8,200 ft) high, at Las Campanas, Chile

     
  • richardmitnick 7:40 pm on March 2, 2020 Permalink | Reply
    Tags: According to Piro and Vissapragada three super-puffs are especially good candidates for rings—Kepler 87c and 177c as well as HIP 41378f., , , , Carnegie Institution For Science, , Some of the extremely low-density “cotton candy like” exoplanets called super-puffs may actually have rings., Super-puffs are notable for having exceptionally large radii for their masses—which would give them seemingly incredibly low densities.   

    From Carnegie Institution for Science: “What if mysterious “cotton candy” planets actually sport rings?” 

    Carnegie Institution for Science
    From Carnegie Institution for Science

    March 02, 2020

    Some of the extremely low-density, “cotton candy like” exoplanets called super-puffs may actually have rings, according to new research published in The Astronomical Journal by Carnegie’s Anthony Piro and Caltech’s Shreyas Vissapragada.

    Super-puffs are notable for having exceptionally large radii for their masses—which would give them seemingly incredibly low densities. The adorably named bodies have been confounding scientists since they were first discovered, because they are unlike any planets in our Solar System and challenge our ideas of what distant planets can be like.

    “We started thinking, what if these planets aren’t airy like cotton candy at all,” Piro said. “What if the super-puffs seem so large because they are actually surrounded by rings?”

    1
    An artist’s conception of Piro and Vissapragada’s model of a ringed planet transiting in front of its host star. They used these models to constrain which of the known super-puffs could be explained by rings. Illustration is by Robin Dienel and courtesy of the Carnegie Institution for Science.

    In our own Solar System, all of the gas and ice giant planets have rings, with the most well-known example being the majestic rings of Saturn. But it has been difficult for astronomers to discover ringed planets orbiting distant stars.

    The radii of exoplanets are measured during transits—when the exoplanet crosses in front of its host star causing a dip in the star’s light.

    Planet transit. NASA/Ames.

    The greater the size of the dip, the larger the exoplanet.

    “We started to wonder, if you were to look back at us from a distant world, would you recognize Saturn as a ringed planet, or would it appear to be a puffy planet to an alien astronomer?” Vissapragada asked.

    To test this hypothesis, Piro and Vissapragada simulated how a ringed exoplanet would look to an astronomer with high-precision instruments watching it transit in front of its host star. They also investigated the types of ring material that could account for observations of super-puffs.

    Their work demonstrated that rings could explain some, but not all, of the super-puffs that NASA’s Kepler mission has discovered so far.

    NASA/Kepler Telescope, and K2 March 7, 2009 until November 15, 2018

    “These planets tend to orbit in close proximity to their host stars, meaning that the rings would have to be rocky, rather than icy,” Piro explained. “But rocky ring radii can only be so big, unless the rock is very porous, so not every super-puff would fit these constraints.”

    According to Piro and Vissapragada, three super-puffs are especially good candidates for rings—Kepler 87c and 177c as well as HIP 41378f.

    Follow-up observations to confirm their work won’t be possible until NASA’s James Webb Space Telescope launches next year, because existing land- and space-based telescopes lack the precision to confirm the presence of rings around these distant worlds.

    If some of the super-puffs could be confirmed as ringed, this would improve astronomers’ understanding of how these planetary systems formed and evolved around their host stars.

    See the full article here .


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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Carnegie Institution of Washington Bldg

    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.

    Carnegie 6.5 meter Magellan Baade and Clay Telescopes located at Carnegie’s Las Campanas Observatory, Chile. over 2,500 m (8,200 ft) high


    6.5 meter Magellan Telescopes located at Carnegie’s Las Campanas Observatory, Chile


    Carnegie Las Campanas 2.5 meter Irénée Dupont telescope, Atacama Desert, over 2,500 m (8,200 ft) high approximately 100 kilometres (62 mi) northeast of the city of La Serena,Chile


    Carnegie Institution Swope telescope at Las Campanas, Chile, 100 kilometres (62 mi) northeast of the city of La Serena. near the north end of a 7 km (4.3 mi) long mountain ridge. Cerro Las Campanas, near the southern end and over 2,500 m (8,200 ft) high, at Las Campanas, Chile

     
  • richardmitnick 5:53 pm on December 20, 2019 Permalink | Reply
    Tags: "Runaway star was ejected from the 'heart of darkness'”, , , , Carnegie Institution For Science,   

    From Carnegie Institution for Science: “Runaway star was ejected from the ‘heart of darkness’” 

    Carnegie Institution for Science
    From Carnegie Institution for Science

    5
    An artist’s concept of the ultrafast star S5-HSV1, which was ejected from the Milky Way by the supermassive black hole at the galaxy’s center. Illustration by James Josephides, courtesy of Swinburne Astronomy Productions.

    A star traveling at ultrafast speeds after being ejected by the supermassive black hole at the heart of our galaxy was spotted by an international team of astronomers including Carnegie’s Ting Li and Alex Ji. Their work is published by Monthly Notices of the Royal Astronomical Society. Hurtling at the blistering speed of 6 million kilometers per hour, the star is moving so fast that it will leave the Milky Way and head into intergalactic space.

    Called S5-HVS1, the star was discovered in the Grus, or Crane, constellation by lead author Sergey Koposov of Carnegie Mellon University as part of the Southern Stellar Stream Spectroscopic Survey led by Carnegie Princeton Fellow Li. It was moving 10-times faster than most of the stars in the galaxy.

    “The velocity of the discovered star is so high that it will inevitably leave the Galaxy and never return,” said co-author Douglas Boubert of the University of Oxford.

    High-velocity stars have been a source of great curiosity for astronomers since their discovery two decades ago. Because S5-HVS1 is moving so quickly and passed relatively close to Earth—29,000 light-years, which is practically next door by astronomical standards—it presented an unprecedented opportunity to better understand these phenomena. Due to these unique circumstances, the researchers were able to trace its journey right back to the center of the Milky Way, where there lurks black hole that’s 4 million times the mass of the Sun.

    “This is super exciting, as we have long suspected that black holes can eject stars with very high velocities. However, we never had an unambiguous association of such a fast star with the Galactic Center,” said Koposov. “We think the black hole ejected the star with a speed of thousands of kilometers per second about five million years ago. This ejection happened at the time when humanity’s ancestors were just learning to walk on two feet.”

    Thirty years ago, astronomer Jack Hills proposed that superfast stars could be ejected by black holes via a process bearing his name.

    “This is the first clear demonstration of the Hills Mechanism in action,” Li said.

    “Seeing this star is really amazing”, she added, “as we know it must have formed in the Galactic Center, a place very different to our local environment. It is a visitor from a strange land.”

    2
    Originally, S5-HSV1 lived with a companion in a binary system, but they strayed too close to Sagittarius A, the supermassive black hole at the center of the Milky Way. In the ensuing gravitational tussle, the companion star was captured by the black hole, while S5-HVS1 was thrown out at extremely high speed. An artist’s impression of the ejection mechanism by the supermassive black hole.

    “My favorite part of this discovery is thinking about where this star came from and where it’s going,” said Ji. “It was born in one of the craziest places in the universe, near a supermassive black hole with lots of other nearby star friends; but it’s going to leave our galaxy and die all alone, out in the middle of nowhere. Quite a fall from grace.”

    The initial discovery was made on the Anglo-Australian Telescope and coupled with observations from the European Space Agency’s Gaia satellite, which allowed the astronomers to reveal the full speed of the star and its journey.


    AAO Anglo Australian Telescope near Siding Spring, New South Wales, Australia, Altitude 1,100 m (3,600 ft)

    ESA/GAIA satellite

    “The observations would not be possible without the unique capabilities of the 2dF instrument on the AAT,” said Daniel Zucker, an astronomer at Macquarie University in Sydney and a member of the S5 Executive Committee.

    “I am so excited this fast-moving star was discovered by S5,” added Kyler Kuehn of Lowell Observatory and another member of the S5 Executive Committee. “While the main science goal of S5 is to probe the stellar streams—disrupting dwarf galaxies and globular clusters—we dedicated spare resources of the instrument to searching for interesting targets in the Milky Way, and voila, we found something amazing for ‘free.’”


    Video by James Josephides, courtesy of Swinburne Astronomy Productions.

    See the full article here .


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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Carnegie Institution of Washington Bldg

    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.

    Carnegie 6.5 meter Magellan Baade and Clay Telescopes located at Carnegie’s Las Campanas Observatory, Chile. over 2,500 m (8,200 ft) high


    6.5 meter Magellan Telescopes located at Carnegie’s Las Campanas Observatory, Chile


    Carnegie Las Campanas 2.5 meter Irénée Dupont telescope, Atacama Desert, over 2,500 m (8,200 ft) high approximately 100 kilometres (62 mi) northeast of the city of La Serena,Chile


    Carnegie Institution Swope telescope at Las Campanas, Chile, 100 kilometres (62 mi) northeast of the city of La Serena. near the north end of a 7 km (4.3 mi) long mountain ridge. Cerro Las Campanas, near the southern end and over 2,500 m (8,200 ft) high, at Las Campanas, Chile

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

    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 .


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

    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 11:06 am on August 6, 2019 Permalink | Reply
    Tags: "Geoengineering versus a volcano", , Carnegie Institution For Science, , ,   

    From Carnegie Institution for Science: “Geoengineering versus a volcano” 

    Carnegie Institution for Science
    From Carnegie Institution for Science

    August 05, 2019

    1
    A photo of the eruption of Mount Pinatubo by Jackson K., courtesy of USGS.

    Major volcanic eruptions spew ash particles into the atmosphere, which reflect some of the Sun’s radiation back into space and cool the planet. But could this effect be intentionally recreated to fight climate change? A new paper in Geophysical Research Letters investigates.

    Solar geoengineering is a theoretical approach to curbing the effects of climate change by seeding the atmosphere with a regularly replenished layer of intentionally released aerosol particles. Proponents sometimes describe it as being like a “human-made” volcano.

    “Nobody likes the idea of intentionally tinkering with our climate system at global scale,” said Carnegie’s Ken Caldeira. “Even if we hope these approaches won’t ever have to be used, it is really important that we understand them because someday they might be needed to help alleviate suffering.”

    He, along with Carnegie’s Lei Duan (a former student from Zhejiang University), Long Cao of Zhejiang University, and Govindasamy Bala of the Indian Institute of Science, set out to compare the effects on the climate of a volcanic eruption and of solar geoengineering. They used sophisticated models to investigate the impact of a single volcano-like event, which releases particulates that linger in the atmosphere for just a few years, and of a long-term geoengineering deployment, which requires maintaining an aerosol layer in the atmosphere.

    They found that regardless of how it got there, when the particulate material is injected into the atmosphere, there is a rapid decrease in surface temperature, with the land cooling faster than the ocean.

    However, the volcanic eruption created a greater temperature difference between the land and sea than did the geoengineering simulation. This resulted in different precipitation patterns between the two scenarios. In both situations, precipitation decreases over land—meaning less available water for many people living there—but the decrease was more significant in the aftermath of a volcanic eruption than it was in the geoengineering case.

    “When a volcano goes off, the land cools substantially quicker than the ocean. This disrupts rainfall patterns in ways that you wouldn’t expect to happen with a sustained deployment of a geoengineering system,” said lead author Duan.

    Overall, the authors say that their results demonstrate that volcanic eruptions are imperfect analogs for geoengineering and that scientists should be cautious about extrapolating too much from them.

    “While it’s important to evaluate geoengineering proposals from an informed position, the best way to reduce climate risk is to reduce emissions,” Caldeira concluded.

    See the full article here .


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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Carnegie Institution of Washington Bldg

    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.

    6.5 meter Magellan Telescopes located at Carnegie’s Las Campanas Observatory, Chile.
    6.5 meter Magellan Telescopes located at Carnegie’s Las Campanas Observatory, Chile


    Carnegie Las Campanas 2.5 meter Irénée Dupont telescope, Atacama Desert, over 2,500 m (8,200 ft) high approximately 100 kilometres (62 mi) northeast of the city of La Serena,Chile


    Carnegie Institution Swope telescope at Las Campanas, Chile, 100 kilometres (62 mi) northeast of the city of La Serena. near the north end of a 7 km (4.3 mi) long mountain ridge. Cerro Las Campanas, near the southern end and over 2,500 m (8,200 ft) high, at Las Campanas, Chile

    [/caption]

     
  • richardmitnick 1:28 pm on July 30, 2019 Permalink | Reply
    Tags: "Study reveals new structure of gold at extremes", , , Carnegie Institution For Science, Increase in pressure and temperature changes the crystalline structure to a new phase of gold., , ,   

    From Lawrence Livermore National Laboratory: “Study reveals new structure of gold at extremes” 

    From Lawrence Livermore National Laboratory

    July 30, 2019
    Breanna Bishop
    bishop33@llnl.gov
    925-423-9802

    1
    Three of the images collected at Argonne National Laboratory’s Dynamic Compression Sector, highlighting diffracted signals recorded on the X-ray detector.

    Section 1 shows the starting face-centered cubic structure; Section 2 shows the new body-centered cubic structure at 220 GPa; and Section 3 shows the liquid gold at 330 GPa.

    Gold is an extremely important material for high-pressure experiments and is considered the “gold standard” for calculating pressure in static diamond anvil cell experiments. When compressed slowly at room temperature (on the order of seconds to minutes), gold prefers to be the face-centered cubic (fcc) structure at pressures up to three times the center of the Earth.

    However, researchers from Lawrence Livermore National Laboratory (LLNL) and the Carnegie Institution for Science have found that when gold is compressed rapidly over nanoseconds (1 billionth of a second), the increase in pressure and temperature changes the crystalline structure to a new phase of gold.

    This well-known body-centered cubic (bcc) structure morphs to a more open crystal structure than the fcc structure. These results were published recently in Physical Review Letters.

    “We discovered a new structure in gold that exists at extreme states — two thirds of the pressure found at the center of Earth,” said lead author Richard Briggs, a postdoctoral researcher at LLNL. “The new structure actually has less efficient packing at higher pressures than the starting structure, which was surprising considering the vast amount of theoretical predictions that pointed to more tightlypacked structures that should exist.”

    The experiments were carried out at the Dynamic Compression Sector (DCS) at the Advanced Photon Source, Argonne National Laboratory.

    ANL Advanced Photon Source

    DCS is the first synchrotron X-ray facility dedicated to dynamic compression science. These user experiments were some of the first conducted on hutch-C, the dedicated high energy laser station of DCS. Gold was the ideal subject to study due to its high-Z (providing a strong X-ray scattering signal) and relatively unexplored phase diagram at high temperatures.

    The team found that that the structure of gold began to change at a pressure of 220 GPa (2.2 million times Earth’s atmospheric pressure) and started to melt when compressed beyond 250 GPa.

    “The observation of liquid gold at 330 GPa is astonishing,” Briggs said. “This is the pressure at the center of the Earth and is more than 300 GPa higher than previous measurements of liquid gold at high pressure.”

    The transition from fcc to bcc structure is perhaps one of the most studied phase transitions due to its importance in the manufacturing of steel, where high temperatures or stress causes a change in structure between the two fcc/bcc structures. However, it is not known what phase transition mechanism is responsible. The research team’s results show that gold undergoes the same phase transition before it melts, as a consequence of both pressure and temperature, and future experiments focusing on the mechanism of the transition can help clarify key details of this important transition for manufacturing strong steels.

    “Many of the theoretical models of gold that are used to understand the high-pressure/high-temperature behavior did not predict the formation of a body-centered structure – only two out of more than 10 published works,” Briggs said. “Our results can help theorists improve their models of elements under extreme compression and look toward using those new models to examine the effects of chemical bonding to aid the development of new materials that can be formed at extreme states.”

    Briggs was joined on the publication by co-authors Federica Coppari, Martin Gorman, Ray Smith, Amy Coleman, Amalia Fernandez-Panella, Marius Millot, Jon Eggert and Dane Fratanduono from LLNL, and Sally Tracy from the Carnegie Institution of Washington’s Geophysical Laboratory.

    See the full article here .


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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    LLNL Campus

    Operated by Lawrence Livermore National Security, LLC, for the Department of Energy’s National Nuclear Security Administration
    Lawrence Livermore National Laboratory (LLNL) is an American federal research facility in Livermore, California, United States, founded by the University of California, Berkeley in 1952. A Federally Funded Research and Development Center (FFRDC), it is primarily funded by the U.S. Department of Energy (DOE) and managed and operated by Lawrence Livermore National Security, LLC (LLNS), a partnership of the University of California, Bechtel, BWX Technologies, AECOM, and Battelle Memorial Institute in affiliation with the Texas A&M University System. In 2012, the laboratory had the synthetic chemical element livermorium named after it.
    LLNL is self-described as “a premier research and development institution for science and technology applied to national security.” Its principal responsibility is ensuring the safety, security and reliability of the nation’s nuclear weapons through the application of advanced science, engineering and technology. The Laboratory also applies its special expertise and multidisciplinary capabilities to preventing the proliferation and use of weapons of mass destruction, bolstering homeland security and solving other nationally important problems, including energy and environmental security, basic science and economic competitiveness.

    The Laboratory is located on a one-square-mile (2.6 km2) site at the eastern edge of Livermore. It also operates a 7,000 acres (28 km2) remote experimental test site, called Site 300, situated about 15 miles (24 km) southeast of the main lab site. LLNL has an annual budget of about $1.5 billion and a staff of roughly 5,800 employees.

    LLNL was established in 1952 as the University of California Radiation Laboratory at Livermore, an offshoot of the existing UC Radiation Laboratory at Berkeley. It was intended to spur innovation and provide competition to the nuclear weapon design laboratory at Los Alamos in New Mexico, home of the Manhattan Project that developed the first atomic weapons. Edward Teller and Ernest Lawrence,[2] director of the Radiation Laboratory at Berkeley, are regarded as the co-founders of the Livermore facility.

    The new laboratory was sited at a former naval air station of World War II. It was already home to several UC Radiation Laboratory projects that were too large for its location in the Berkeley Hills above the UC campus, including one of the first experiments in the magnetic approach to confined thermonuclear reactions (i.e. fusion). About half an hour southeast of Berkeley, the Livermore site provided much greater security for classified projects than an urban university campus.

    Lawrence tapped 32-year-old Herbert York, a former graduate student of his, to run Livermore. Under York, the Lab had four main programs: Project Sherwood (the magnetic-fusion program), Project Whitney (the weapons-design program), diagnostic weapon experiments (both for the Los Alamos and Livermore laboratories), and a basic physics program. York and the new lab embraced the Lawrence “big science” approach, tackling challenging projects with physicists, chemists, engineers, and computational scientists working together in multidisciplinary teams. Lawrence died in August 1958 and shortly after, the university’s board of regents named both laboratories for him, as the Lawrence Radiation Laboratory.

    Historically, the Berkeley and Livermore laboratories have had very close relationships on research projects, business operations, and staff. The Livermore Lab was established initially as a branch of the Berkeley laboratory. The Livermore lab was not officially severed administratively from the Berkeley lab until 1971. To this day, in official planning documents and records, Lawrence Berkeley National Laboratory is designated as Site 100, Lawrence Livermore National Lab as Site 200, and LLNL’s remote test location as Site 300.[3]

    The laboratory was renamed Lawrence Livermore Laboratory (LLL) in 1971. On October 1, 2007 LLNS assumed management of LLNL from the University of California, which had exclusively managed and operated the Laboratory since its inception 55 years before. The laboratory was honored in 2012 by having the synthetic chemical element livermorium named after it. The LLNS takeover of the laboratory has been controversial. In May 2013, an Alameda County jury awarded over $2.7 million to five former laboratory employees who were among 430 employees LLNS laid off during 2008.[4] The jury found that LLNS breached a contractual obligation to terminate the employees only for “reasonable cause.”[5] The five plaintiffs also have pending age discrimination claims against LLNS, which will be heard by a different jury in a separate trial.[6] There are 125 co-plaintiffs awaiting trial on similar claims against LLNS.[7] The May 2008 layoff was the first layoff at the laboratory in nearly 40 years.[6]

    On March 14, 2011, the City of Livermore officially expanded the city’s boundaries to annex LLNL and move it within the city limits. The unanimous vote by the Livermore city council expanded Livermore’s southeastern boundaries to cover 15 land parcels covering 1,057 acres (4.28 km2) that comprise the LLNL site. The site was formerly an unincorporated area of Alameda County. The LLNL campus continues to be owned by the federal government.

    LLNL/NIF


    DOE Seal
    NNSA

     
  • richardmitnick 9:00 am on July 27, 2019 Permalink | Reply
    Tags: "Could this rare supernova resolve a longstanding origin debate?", A major survey of Type Ia supernovae—called 100IAS, Although hydrogen is the most-abundant element in the universe it is almost never seen in Type Ia supernova explosions., ASASSN-18tb is different from these previous events, , , , Carnegie Institution For Science, , Type Ia supernovae originate from the thermonuclear explosion of a white dwarf that is part of a binary system.   

    From Carnegie Institution for Science: “Could this rare supernova resolve a longstanding origin debate?” 

    Carnegie Institution for Science
    From Carnegie Institution for Science

    May 07, 2019

    1
    Cartoon courtesy of Anthony Piro illustrates three possibilities for the origin of the mysterious hydrogen emission from the Type IA supernova called ASASSN-18tb that was observed by Carnegie astronomers.

    2

    Violent Supernova Explosion, ASASSN-18tb, Emitted Large Amounts Of Hydrogen, Scientists Found Out

    Starting from the top and going clockwise: The collision of the explosion with a hydrogen-rich companion star, the explosion triggered by two colliding white dwarf stars subsequently colliding with a third hydrogen-rich star, or the explosion interacting with circumstellar hydrogen material.

    Detection of a supernova with an unusual chemical signature by a team of astronomers led by Carnegie’s Juna Kollmeier—and including Carnegie’s Nidia Morrell, Anthony Piro, Mark Phillips, and Josh Simon—may hold the key to solving the longstanding mystery that is the source of these violent explosions. Observations taken by the Magellan telescopes at Carnegie’s Las Campanas Observatory in Chile [below] were crucial to detecting the emission of hydrogen that makes this supernova, called ASASSN-18tb, so distinctive.

    Their work is published in Monthly Notices of the Royal Astronomical Society.

    Type Ia supernovae play a crucial role in helping astronomers understand the universe. Their brilliance allows them to be seen across great distances and to be used as cosmic mile-markers, which garnered the 2011 Nobel Prize in Physics. Furthermore, their violent explosions synthesize many of the elements that make up the world around us, which are ejected into the galaxy to generate future stars and stellar systems.

    Although hydrogen is the most-abundant element in the universe, it is almost never seen in Type Ia supernova explosions. In fact, the lack of hydrogen is one of the defining features of this category of supernovae and is thought to be a key clue to understanding what came before their explosions. This is why seeing hydrogen emissions coming from this supernova was so surprising.

    Type Ia supernovae originate from the thermonuclear explosion of a white dwarf that is part of a binary system. But what exactly triggers the explosion of the white dwarf—the dead core left after a Sun-like star exhausts its nuclear fuel—is a great puzzle. A prevailing idea is that, the white dwarf gains matter from its companion star, a process that may eventually trigger the explosion, but whether this is the correct theory has been hotly debated for decades.

    This led the research team behind this paper to begin a major survey of Type Ia supernovae—called 100IAS—that was launched when Kollmeier was discussing the origin of these supernovae with study co-authors Subo Dong of Peking University and Doron Kushnir of the Weizmann Institute of Science who, along with Weizmann colleague Boaz Katz, put forward an new theory for Type Ia explosions that involves the violent collision of two white dwarfs.

    Astronomers eagerly study the chemical signatures of the material ejected during these explosions in order to understand the mechanism and players involved in creating Type Ia supernovae.

    In recent years, astronomers have discovered a small number of rare Type Ia supernovae that are cloaked in large amount of hydrogen—maybe as much as the mass of our Sun. But in several respects, ASASSN-18tb is different from these previous events.

    “It’s possible that the hydrogen we see when studying ASASSN-18tb is like these previous supernovae, but there are some striking differences that aren’t so easy to explain,” said Kollmeier.

    First, in all previous cases these hydrogen-cloaked Type Ia supernovae were found in young, star-forming galaxies where plenty of hydrogen-rich gas may be present. But ASASSN-18tb occurred in a galaxy consisting of old stars. Second, the amount of hydrogen ejected by ASASSN-18tb is significantly less than that seen surrounding those other Type Ia supernovae. It probably amounts to about one-hundredth the mass of our Sun.

    “One exciting possibility is that we are seeing material being stripped from the exploding white dwarf’s companion star as the supernova collides with it,” said Anthony Piro. “If this is the case, it would be the first-ever observation of such an occurrence.”

    “I have been looking for this signature for a decade!” said co-author Josh Simon. “We finally found it, but it’s so rare, which is an important piece of the puzzle for solving the mystery of how Type Ia supernovae originate.”

    Nidia Morrell was observing that night, and she immediately reduced the data coming off the telescope and circulated them to the team including Ph.D. student Ping Chen, who works on 100IAS for his thesis and Jose Luis Prieto of Universidad Diego Portales, a veteran supernova observer. Chen was the first to notice that this was not a typical spectrum. All were completely surprised by what they saw in ASASSN-18tb’s spectrum.

    “I was shocked, and I thought to myself ‘could this really be hydrogen?’” recalled Morrell.

    To discuss the observation, Morrell met with team member Mark Phillips, a pioneer in establishing the relationship—informally named after him—that allows Type Ia supernovae to be used as standard rulers. Phillips was convinced: “It is hydrogen you’ve found; no other possible explanation.”

    “This is an unconventional supernova program, but I am an unconventional observer—a theorist, in fact” said Kollmeier. “It’s an extremely painful project for our team to carry out. Observing these things is like catching a knife, because by definition they get fainter and fainter with time! It’s only possible at a place like Carnegie where access to the Magellan telescopes allow us to do time-intensive and sometimes arduous, but extremely important cosmic experiments. No pain, no gain.”

    This research was supported in part by the NSFC.

    See the full article here .


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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Carnegie Institution of Washington Bldg

    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.

    6.5 meter Magellan Telescopes located at Carnegie’s Las Campanas Observatory, Chile.
    6.5 meter Magellan Telescopes located at Carnegie’s Las Campanas Observatory, Chile


    Carnegie Las Campanas 2.5 meter Irénée Dupont telescope, Atacama Desert, over 2,500 m (8,200 ft) high approximately 100 kilometres (62 mi) northeast of the city of La Serena,Chile


    Carnegie Institution Swope telescope at Las Campanas, Chile, 100 kilometres (62 mi) northeast of the city of La Serena. near the north end of a 7 km (4.3 mi) long mountain ridge. Cerro Las Campanas, near the southern end and over 2,500 m (8,200 ft) high, at Las Campanas, Chile

    [/caption]

     
  • richardmitnick 11:36 am on May 4, 2019 Permalink | Reply
    Tags: "When it comes to planetary habitability it’s what’s inside that counts", A true picture of planetary habitability must consider how a planet’s atmosphere is linked to and shaped by what’s happening in its interior, , , , Carnegie Institution For Science, , , , , ,   

    From Carnegie Institution for Science: “When it comes to planetary habitability, it’s what’s inside that counts” 

    Carnegie Institution for Science
    From Carnegie Institution for Science

    May 01, 2019

    Which of Earth’s features were essential for the origin and sustenance of life? And how do scientists identify those features on other worlds?

    A team of Carnegie investigators with array of expertise ranging from geochemistry to planetary science to astronomy published this week in Science an essay urging the research community to recognize the vital importance of a planet’s interior dynamics in creating an environment that’s hospitable for life.

    With our existing capabilities, observing an exoplanet’s atmospheric composition will be the first way to search for signatures of life elsewhere. However, Carnegie’s Anat Shahar, Peter Driscoll, Alycia Weinberger, and George Cody argue that a true picture of planetary habitability must consider how a planet’s atmosphere is linked to and shaped by what’s happening in its interior.

    1
    Reprinted with permission from Shahar et. al., Science Volume 364:3(2019).

    For example, on Earth, plate tectonics are crucial for maintaining a surface climate where life can thrive. What’s more, without the cycling of material between its surface and interior, the convection that drives the Earth’s magnetic field would not be possible and without a magnetic field, we would be bombarded by cosmic radiation.

    “We need a better understanding of how a planet’s composition and interior influence its habitability, starting with Earth,” Shahar said. “This can be used to guide the search for exoplanets and star systems where life could thrive, signatures of which could be detected by telescopes.”

    It all starts with the formation process. Planets are born from the rotating ring of dust and gas that surrounds a young star. The elemental building blocks from which rocky planets form—silicon, magnesium, oxygen, carbon, iron, and hydrogen—are universal. But their abundances and the heating and cooling they experience in their youth will affect their interior chemistry and, in turn, things like ocean volume and atmospheric composition.

    “One of the big questions we need to ask is whether the geologic and dynamic features that make our home planet habitable can be produced on planets with different compositions,” Driscoll explained.

    The Carnegie colleagues assert that the search for extraterrestrial life must be guided by an interdisciplinary approach that combines astronomical observations, laboratory experiments of planetary interior conditions, and mathematical modeling and simulations.

    2
    Artist’s impression of the surface of the planet Barnard’s Star b courtesy of ESO/M. Kornmesser.

    “Carnegie scientists are long-established world leaders in the fields of geochemistry, geophysics, planetary science, astrobiology, and astronomy,” said Weinberger. “So, our institution is perfectly placed to tackle this cross-disciplinary challenge.”

    In the next decade as a new generation of telescopes come online, scientists will begin to search in earnest for biosignatures in the atmospheres of rocky exoplanets. But the colleagues say that these observations must be put in the context of a larger understanding of how a planet’s total makeup and interior geochemistry determines the evolution of a stable and temperate surface where life could perhaps arise and thrive.

    “The heart of habitability is in planetary interiors,” concluded Cody.

    See the full article here .


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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Carnegie Institution of Washington Bldg

    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.

    6.5 meter Magellan Telescopes located at Carnegie’s Las Campanas Observatory, Chile.
    6.5 meter Magellan Telescopes located at Carnegie’s Las Campanas Observatory, Chile


    Carnegie Las Campanas 2.5 meter Irénée Dupont telescope, Atacama Desert, over 2,500 m (8,200 ft) high approximately 100 kilometres (62 mi) northeast of the city of La Serena,Chile


    Carnegie Institution Swope telescope at Las Campanas, Chile, 100 kilometres (62 mi) northeast of the city of La Serena. near the north end of a 7 km (4.3 mi) long mountain ridge. Cerro Las Campanas, near the southern end and over 2,500 m (8,200 ft) high, at Las Campanas, Chile

    [/caption]

     
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