9207(  1) - 12/20/00 23:42  - [  1]

    PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS   ST ScI Use Only
                                                       ID:      9207
                                                       Version: 1
                                                       Check-in Date: 20-Dec-2000
                                                                      23:35:42

1.Proposal Title:
Middle Ultaviolet Spectroscopy of Pluto and Charon
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2. Proposal For  3. Cycle
AR               10
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4. Investigators
                                                                                     Contact?
    PI: Vladimir Krasnopolsky             The Catholic University of America

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5. Abstract

I propose to study the spectra of Pluto in the range of 2000- 2500 Angstrom that
were successfully observed with HST/FOS during 34 ksec (24 orbits) total and have
not been analyzed. My preliminary work with those data resulted in a mean spectrum
with resolution of 10 Angstrom and S/N = 15-20 down to 2100 Angstrom. Our
photochemical model for Pluto predicts the abundances of diacetylene C_4H_2 and
cyanoacetylene HC_3N that may be detectable in the observed spectra. Detection of
any new species on Pluto would be a breakthrough in our knowledge of that planet.
The observed spectra show variations that significantly exceed the experimental
uncertainties, are prominent below 2500 Angstrom, and indicate the presence of fine
haze and/or rime and their variations. I will also study the spectra of Charon at
2200-3300 Angstrom that were also successfully observed with HST/FOS during 21 ksec
(16 orbits) total and have not been analyzed. Averaging of these spectra results in
a spectrum with resolution of 10 Angstrom and S/N >=20 above 2650 Angstrom and
decreasing to ~ 7 at 2200-2500 Angstrom. These spectra are the only data on Charon
in the middle ultraviolet and may add to our knowledge of its ices and rocks. The
proposal covers the successful HST observations for 55 ksec (40 orbits) that
otherwise will be lost.
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                                                9207(  1) - 12/20/00 23:42  - [  2]

            Summary Form for Proposal  9207

  Item                         Used in this proposal
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  Proposal Category            AR
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