DPS 35th Meeting, 1-6 September 2003
Session 23. Planetary Bookends I
Oral, Chairs: W. B. McKinnon and W. M. Grundy, Thursday, September 4, 2003, 10:30am-12:00noon, DeAnza I-II

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[23.06] Pluto and Charon's Visible Spectrum (3500-9000~Å)

J. C. Cook (Arizona State Univeristy), S. Wyckoff (Arizona State University)

Uncertainty in the chemical composition of Pluto's atmosphere severely limits our understanding of its physical properties. The only atmospheric gas identified spectroscopically to date has been CH4 (Young \emph{et al.}, 1997), while an upper limit has been set for CO gas (Young \emph{et al.}, 2001). Infrared detection of surface N2 ice (Owen \emph{et al.}, 1993) together with models based on occultation data (Elliot and Young, 1992) indicate that Pluto's atmosphere is probably dominated by CO and/or N2 (Yelle and Lunine, 1989; Hubbard \emph{et al.}, 1990; Stansberry \emph{et al.}, 1994). If the atmosphere is in vapor pressure equilibrium with the surface ice, then N2 gas would dominate the atmosphere with abundances \gtrsim 90% (Owen \emph{et al.}, 1993). Here we report on a search to identify atmospheric spectral features using data collected with the Steward Observatory 90'' Bok Telescope and the B & C Spectrograph. Pluto-Charon spectra were obtained on five nights in May and June 2003 using 300 l/mm grating blazed in the blue and red spectral regions. We present spectra covering the visible range from 3500 to 9000 Å: (\lambda/\Delta \lambda ~750 at 6000 Å), and discuss limits set on gases in the atmosphere and extended exosphere of the Pluto-Charon system.

J. C. Cook would like to acknowledge support from NASA Space Grant Fellowship.

The author(s) of this abstract have provided an email address for comments about the abstract: Jason.Cook3@asu.edu

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Bulletin of the American Astronomical Society, 35 #4
© 2003. The American Astronomical Soceity.