Detection of the water reservoir in a forming planetary system.
Icy bodies may have delivered the oceans to the early Earth, yet little is known about water in the ice-dominated regions of extrasolar planet-forming disks. The Heterodyne Instrument for the Far-Infrared on board the Herschel Space Observatory has detected emission lines 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.
Leiden Observatory, Leiden University, Post Office Box 9513, 2300 RA Leiden, Netherlands. michiel@strw.leidenuniv.nl
Michiel R
MR
Hogerheijde
Edwin A
EA
Bergin
Christian
C
Brinch
L Ilsedore
LI
Cleeves
Jeffrey K J
JK
Fogel
Geoffrey A
GA
Blake
Carsten
C
Dominik
Dariusz C
DC
Lis
Gary
G
Melnick
David
D
Neufeld
Olja
O
Panić
John C
JC
Pearson
Lars
L
Kristensen
Umut A
UA
Yildiz
Ewine F
EF
van Dishoeck
D019419:Evolution, Planetary; D005118:Extraterrestrial Environment; D007053:Ice; D016083:Planets; D055609:Stars, Celestial; D013227:Steam
D007053:Ice; D013227:Steam