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Detection of abundant ethane and methane, along with carbon monoxide and water, in comet C/1996 B2 Hyakutake: evidence for interstellar originThe saturated hydrocarbons ethane (C2H6) and methane (CH4) along with carbon monoxide (CO) and water (H2O) were detected in comet C/1996 B2 Hyakutake with the use of high-resolution infrared spectroscopy at the NASA Infrared Telescope Facility on Mauna Kea, Hawaii. The inferred production rates of molecular gases from the icy, cometary nucleus (in molecules per second) are 6.4 X 10(26) for C2H6, 1.2 X 10(27) for CH4, 9.8 X 10(27) for CO, and 1.7 X 10(29) for H2O. An abundance of C2H6 comparable to that of CH4 implies that ices in C/1996 B2 Hyakutake did not originate in a thermochemically equilibrated region of the solar nebula. The abundances are consistent with a kinetically controlled production process, but production of C2H6 by gas-phase ion molecule reactions in the natal cloud core is energetically forbidden. The high C2H6/CH4 ratio is consistent with production of C2H6 in icy grain mantles in the natal cloud, either by photolysis of CH4-rich ice or by hydrogen-addition reactions to acetylene condensed from the gas phase.
Document ID
20040173211
Document Type
Reprint (Version printed in journal)
Authors
Mumma, M. J. (NASA Goddard Space Flight Center Greenbelt, MD United States)
DiSanti, M. A.
Dello Russo, N.
Fomenkova, M.
Magee-Sauer, K.
Kaminski, C. D.
Xie, D. X.
Date Acquired
August 22, 2013
Publication Date
May 31, 1996
Publication Information
Publication: Science
Volume: 272
Issue: 5266
ISSN: 0036-8075
Subject Category
Lunar and Planetary Science and Exploration
Distribution Limits
Public
Copyright
Other
Keywords
Non-programmatic