Upper limits on gaseous CO at Pluto and Triton from high-resolution near-IR spectroscopy

Citation
La. Young et al., Upper limits on gaseous CO at Pluto and Triton from high-resolution near-IR spectroscopy, ICARUS, 153(1), 2001, pp. 148-156
Citations number
56
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Space Sciences
Journal title
ICARUS
ISSN journal
0019-1035 → ACNP
Volume
153
Issue
1
Year of publication
2001
Pages
148 - 156
Database
ISI
SICI code
0019-1035(200109)153:1<148:ULOGCA>2.0.ZU;2-V
Abstract
We observed Pluto and Triton with the CSHELL echelle spectrograph on the In frared Telescope Facility in April and July 1996, in an effort to detect th e R(2), R(3), and R(4) rotational lines of the 2-0 vibrational transition o f gaseous CO. As no lines were detected, we derived 3-sigma upper limits on the average widths of these three lines of 0.040 cm(-1) for Pluto and 0.02 8 cm(-1) for Triton. The corresponding upper limits on the gaseous CO mole fractions depend on the assumed profiles of temperature and pressure in the atmospheres of these bodies. If Triton's atmosphere in 1996 resembles that measured by stellar occultation in 1997, we find a 3-sigma upper limit to the CO mole fraction of 59%. If Pluto's atmosphere resembles the tropospher ic model of J. A. Stansberry, J. I. Lunine, W. B. Hubbard, R. V. Yelle, and D. M. Hunten (1994), Icarus 11, 503-513, we find a 3-sigma upper limit to the CO mole fraction of 6%. For Pluto, this limit to the gaseous mole fract ion argues against intimate mixtures (e.g., "salt-and-pepper" mixtures, as opposed to solid solutions) of surface CO and N-2 frost. sigma 2001 Academi c Press.