[Previous] | [Session 30] | [Next]
H. Campins, D. McCarthy, S. Kern (U. of Arizona), H.A. Weaver (Johns Hopkins U.), R.H. Brown (U. of Arizona)
A number of arguments suggest that near-Earth object 3200 Phaethon has a cometary origin. Information about its surface composition may provide additional clues about its origin and evolution. To date, the surface composition of 3200 Phaethon is not well constrained (e.g., Hicks et al. 1998). We obtained a spectrum of 3200 Phaethon on UT Nov. 13.94, 1998, using the Hubble Space Telescope's Near Infrared Camera and Multi Object Spectrometer (NICMOS). Observations were made with NICMOS Camera 3, using grisms G096, G141 and G206, which span the 0.9 to 2.5 micron region. At the time of the observations 3200 Phaethon was near opposition, at heliocentric and geocentric distances of 2.3 AU and 1.4 AU, respectively. The phase angle was approximatley 9 degrees. Reduction of the data has been more difficult than anticipated, mainly due to intrapixel sensitivity variations. Nevertheless, we have successfully reduced and calibrated the spectrum. Our results are consistent with the ground based spectrum from 1.5-2.5 microns obtained by Dumas, Owen and Barucci (1998). In addition, we have identified shallow but distinct spectral features at wavelengths not covered by the ground based spectra. The modeling and interpretation of these features will be presented.