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Posts Tagged ‘cosmochemistry’

An Unprecedented View Of Two Hundred Galaxies Of The Local Universe

October 2, 2014 Leave a comment

Galaxies are the result of an evolutionary process started thousands of million years ago, and their history is coded in their distinct components. The CALIFA project is intended to decode the galaxies’ history in a sort of galactic archaeology, through the 3D observations of a sample of six hundred galaxies. With this second data release corresponding to two hundred galaxies, the project reaches its halfway point with important results behind.

The CALIFA Project allows not only to inspect the galaxies in detail, but it also provides with data on the evolution of each particular galaxy with time: how much gas and when was it converted into stars along each phase of the galaxy’s life, and how did each region of the galaxies evolve along the more than ten thousand million years of cosmic evolution.

Thanks to the CALIFA data, the astronomers have been able to deduce the history of the mass, luminosity and chemical evolution of the CALIFA sample of galaxies, and thus they have found that more massive galaxies grow faster than less massive ones, and that they form their central regions before the external ones (inside-out mass assembly).

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ASU Astrophysicists To Probe How Early Universe Made Chemical Elements

September 11, 2014 Leave a comment

Photo by: Gemini Observatory artwork by Lynette Cook

Photo by: Gemini Observatory artwork by Lynette Cook

In the beginning, all was hydrogen – and helium, plus a bit of lithium. Three elements in all. Today’s universe, however, has nearly a hundred naturally occurring elements, with thousands of variants (isotopes), and more likely to come.

Figuring out how the universe got from its starting batch of three elements to the menagerie found today is the focus of a new Physics Frontiers Center research grant to Arizona State University’s School of Earth and Space Exploration (SESE). The grant is from the National Science Foundation’s Joint Institute for Nuclear Astrophysics – Center for the Evolution of the Elements. Of the full $11.4 million NSF grant, about $1 million will come to ASU over five years.

SESE astrophysicist Frank Timmes is the lead scientist for ASU’s part of the Physics Frontiers Center research project. Timmes, ASU’s director of advanced computing, focuses his astrophysical research on supernovae, cosmic chemical evolution, their impacts on astrobiology and high-performance computing. He is also a scientific editor of The Astrophysical Journal.

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Icy Aquifers On Titan Transform Methane Rainfall

September 4, 2014 Leave a comment

The NASA and European Space Agency Cassini mission has revealed hundreds of lakes and seas spread across the north polar region of Saturn’s moon Titan. These lakes are filled not with water but with hydrocarbons, a form of organic compound that is also found naturally on Earth and includes methane. The vast majority of liquid in Titan’s lakes is thought to be replenished by rainfall from clouds in the moon’s atmosphere. But how liquids move and cycle through Titan’s crust and atmosphere is still relatively unknown.

A recent study led by Olivier Mousis, a Cassini research associate at the University of Franche-Comté, France, examined how Titan’s methane rainfall would interact with icy materials within underground reservoirs. They found that the formation of materials called clathrates changes the chemical composition of the rainfall runoff that charges these hydrocarbon “aquifers.” This process leads to the formation of reservoirs of propane and ethane that may feed into some rivers and lakes

“We knew that a significant fraction of the lakes on Titan’s surface might possibly be connected with hidden bodies of liquid beneath Titan’s crust, but we just didn’t know how they would interact,” said Mousis. “Now, we have a better idea of what these hidden lakes or oceans could be like.”

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ALMA Confirms Comets Forge Organic Molecules In Their Dusty Atmospheres

August 12, 2014 Leave a comment

The emission from organic molecules in the atmosphere of comet ISON as observed with ALMA. Credit: B. Saxton (NRAO/AUI/NSF); M. Cordiner, NASA, et al.

The emission from organic molecules in the atmosphere of comet ISON as observed with ALMA. Credit: B. Saxton (NRAO/AUI/NSF); M. Cordiner, NASA, et al.

An international team of scientists using the Atacama Large Millimeter/submillimeter Array (ALMA) has made incredible 3D images of the ghostly atmospheres surrounding comets ISON and Lemmon. These new observations provided important insights into how and where comets forge new chemicals, including intriguing organic compounds.

Comets contain some of the oldest and most pristine materials in our Solar System. Understanding their unique chemistry could reveal much about the birth of our planet and the origin of organic compounds that are the building blocks of life. ALMA’s high-resolution observations provided a tantalizing 3D perspective of the distribution of the molecules within these two cometary atmospheres, or comas.

“We achieved truly first-of-a-kind mapping of important molecules that help us understand the nature of comets,” said team leader Martin Cordiner, a Catholic University of America astrochemist working at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

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NASA’s 3-D Study Of Comets Reveals Chemical Factory At Work

August 12, 2014 Leave a comment

A NASA-led team of scientists has created detailed 3-D maps of the atmospheres surrounding comets, identifying several gases and mapping their spread at the highest resolution ever achieved.

“We achieved truly first-of-a-kind mapping of important molecules that help us understand the nature of comets,” said Martin Cordiner, a researcher working in the Goddard Center for Astrobiology at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. Cordiner led the international team of researchers.

Almost unheard of for comet studies, the 3-D perspective provides deeper insight into which materials are shed from the nucleus of the comet and which are produced within the atmosphere, or coma. This helped the team nail down the sources of two key organic, or carbon-containing, molecules.

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Astronomers Identify Signature Of Earth-Eating Stars


Some Sun-like stars are ‘Earth-eaters.’ During their development they ingest large amounts of the rocky material from which ‘terrestrial’ planets like Earth, Mars and Venus are made.

Trey Mack, a graduate student in astronomy at Vanderbilt University, has developed a model that estimates the effect that such a diet has on a star’s chemical composition and has used it to analyze a pair of twin stars that both have their own planets.

The results of the study were published online May 7 in the Astrophysical Journal.

“Trey has shown that we can actually model the chemical signature of a star in detail, element by element, and determine how that signature is changed by the ingestion of Earth-like planets,” said Vanderbilt Professor of Astronomy Keivan Stassun, who supervised the study. “After obtaining a high-resolution spectrum for a given star, we can actually detect that signature in detail, element by element.”

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Subaru Telescope Detects Rare Form Of Nitrogen In Comet ISON

February 24, 2014 Leave a comment

A team of astronomers, led by Ph.D. candidate Yoshiharu Shinnaka and Professor Hideyo Kawakita, both from Kyoto Sangyo University, successfully observed the Comet ISON during its bright outburst in the middle of November 2013. Subaru Telescope’s High Dispersion Spectrograph (HDS) detected two forms of nitrogen–14NH2 and 15NH2–in the comet. This is the first time that astronomers have reported a clear detection of the relatively rare isotope 15NH2 in a single comet and also measured the relative abundance of two different forms of nitrogen (“nitrogen isotopic ratio”) of cometary ammonia (NH3). Their results support the hypothesis that there were two distinct reservoirs of nitrogen the massive, dense cloud (“solar nebula”) from which our Solar System may have formed and evolved.

Why did the team focus on studying these different forms of nitrogen in the comet? Comets are relatively small Solar System objects composed of ice and dust, which formed 4.6 billion years ago in the solar nebula when our Solar System was in its infancy. Because they usually reside in cold regions far from the Sun, e.g., the Kuiper belt and Oort cloud, they probably preserve information about the physical and chemical conditions in the early Solar System. Different forms and abundances of the same molecule provide information about their source and evolution. Were they from a stellar nursery (a primordial interstellar cloud) or from a distinctive cloud (solar nebula) that may have formed our Solar System’s star, the Sun? Scientists do not yet understand very well how cometary molecules separate into isotopes with different abundances. Isotopes of nitrogen from ammonia (NH3) may hold the key.

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