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Isotopic Ratios of Carbon and Oxygen in Titan's CO Using AlmaWe report interferometric observations of carbon monoxide (CO) and its isotopologues in Titan's atmosphere using the Atacama Large Millimeter/submillimeter Array (ALMA). The following transitions were detected: CO (J = 1-0, 2-1, 3-2, 6-5), C-13 O (J = 2-1, 3-2, 6-5), C-18 O (J = 2-1, 3-2), and C-17 O (J = 3-2). Molecular abundances and the vertical atmospheric temperature profile were derived by modeling the observed emission line profiles using NEMESIS, a line-by-line radiative transfer code. We present the first spectroscopic detection of O-17 in the outer solar system with C-17 O detected at greater than 8 sigma confidence. The abundance of CO was determined to be 49.6 +/- 1.8 ppm, assumed to be constant with altitude, with isotopic ratios C-12/C-13 = 89.9 +/- 3.4, O-16/O-18 = 486 +/- 22, and O-16/O-17 = 2917 +/- 359. The measurements of C-12/C-13 and O-16/O-18 ratios are the most precise values obtained in Titan's atmospheric CO to date. Our results are in good agreement with previous studies and suggest no significant deviations from standard terrestrial isotopic ratios.
Document ID
20170002452
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
Authors
Serigano, Joseph
(Catholic Univ. of America Washington, DC, United States)
Nixon, C. A.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Cordiner, M. A.
(Catholic Univ. of America Washington, DC, United States)
Irwin, P. G. J.
(Oxford Univ. Oxford, United Kingdom)
Teanby, N. A.
(Bristol Univ. United Kingdom)
Charnley, S. B.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Lindberg, J. E.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Date Acquired
March 23, 2017
Publication Date
April 7, 2016
Publication Information
Publication: Astrophysical Journal Letters
Publisher: IOP Publishing
Volume: 821
Issue: 1
ISSN: 2041-8205
e-ISSN: 2041-8213
Subject Category
Lunar And Planetary Science And Exploration
Report/Patent Number
GSFC-E-DAA-TN40350
Distribution Limits
Public
Copyright
Other

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