Michiel R. Hogerheijde, Edwin A. Bergin, Christian Brinch, L. Ilsedore Cleeves, Jeffrey K. J. Fogel, Geoffrey A. Blake, Carsten Dominik, Dariusz C. Lis, Gary Melnick, David Neufeld, Olja Panic, John C. Pearson, Lars Kristensen, Umut A. Yildiz, Ewine F. van Dishoeck
Icy bodies may have delivered the oceans to the early Earth, yet little is
known about water in the ice-dominated regions of extra-solar planet-forming
disks. The Heterodyne Instrument for the Far-Infrared on-board the Herschel
Space Observatory has detected emission from both spin isomers of cold water
vapor from the disk around the young star TW Hydrae. This water vapor likely
originates from ice-coated solids near the disk surface hinting at a water ice
reservoir equivalent to several thousand Earth Oceans in mass. The water's
ortho-to-para ratio falls well below that of Solar System comets, suggesting
that comets contain heterogeneous ice mixtures collected across the entire
solar nebula during the early stages of planetary birth.
View original:
http://arxiv.org/abs/1110.4600
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