HR: 0800h
AN: P11B-0123    [Abstracts]
TI: UV Spectroscopy for Remote Sensing of Planetary Materials
AU: * Williams, J c
EM: joseph.williams@hamptonu.edu
AB: UV spectroscopy is a fundamental tool for observing airless planets, moons, and asteroids from spacecraft and from Earth orbit. Such observations can provide answers to central scientific questions, such as how the volatile elements basic to life are distributed in the solar system. Yet the best laboratory data against which UV spectroscopic observations can be evaluated is nearly 20 years old and limited in scope. Thus, the wealth of UV spectra of planetary surfaces that exists now and will be obtained in the future from various spacecraft missions cannot be fully interpreted due to a lack of existing laboratory data. Our program plans to fill this need by performing laboratory measurements of UV spectra of candidate substances under conditions relevant to outer space bodies. We intend to generate a laboratory archive database for analysis of past (Galileo, Hubble Space Telescope [HST], Mariner 9, International Ultraviolet Explorer [IUE], on-going (Cassini, HST) and future missions (MESSENGER, Jupiter Icy Moons Orbiter [JIMO]). This report is on the analysis of UV spectral data of Europa's surface obtained by the Galileo spacecraft. Initial laboratory measurements at NASA JPL (Carlson, et al, 1999) indicate that H2O2 at about 0.13 % in H2O matches well with Galileo UVS data between about 300 to 210 nm. The actual Europa surface concentration of H2O2 remains uncertain because the value calculated from the laboratory measurements is based on the use of 296 K liquid-phase absorption coefficients determined about 25 years ago, which may be inaccurate for H2O2 in low temperature ice. Also, numerous substances exhibit broadband UV absorption spectra. This accentuates the need for more extensive laboratory measurements at appropriate conditions, which our program is addressing.
DE: 1060 Planetary geochemistry (5405, 5410, 5704, 5709, 6005, 6008)
DE: 5464 Remote sensing
DE: 6221 Europa
DE: 6281 Titan
DE: 6297 Instruments and techniques
SC: Planetary Sciences [P]
MN: Fall Meeting 2005