Archive for May 20, 2014

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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Hidden Nurseries In The Milky Way

APEX, the Atacama Pathfinder Experiment, is a telescope of 12 m diameter at an exceptional site on Earth: the Chajnantor plateau is located 5100 m above sea level in the Atacama desert in Chile. It was used to map the whole inner part of the plane of our Milky Way, ranging from the Southern constellations of Vela and Carina all the way to the Northern constellations of Aquila and the great Cygnus rift. The APEX Telescope Large Area Survey of the Galaxy (ATLASGAL) mapped the Galactic Plane at a wavelength of 0.87 mm. Cold interstellar dust emits strongly in this part of the electromagnetic spectrum, called the sub-millimeter range, while it is blocking visible and infrared wavelengths. The survey has revealed an unprecedented number of cold dense clumps of gas and dust as the cradles of massive stars, thus providing a complete view of their birthplaces in the Milky Way. Based on this census, an international team of scientists led by Timea Csengeri from the Max Planck Institute for Radio Astronomy in Bonn has estimated the time scale for these nurseries to grow stars. This has been found to be a very fast process: with only 75,000 years on average it is much shorter than the corresponding time scales typically found for nurseries of lower mass stars.

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