Swift UV Observations of the Evolution of Comet 8p/Tuttle
Abstract
The abundance of native ices in comet nuclei is a fundamental observational constraint in cosmogony. An important unresolved question is the extent to which the composition of pre-cometary ices varied with distance from the young sun. Our fundamental objective is to build a taxonomy based on cometary volatile composition instead of orbital dynamics [1].
The Swift space telescope [2] is unique in combining gamma ray, UV and X-ray instruments. Swift's UV-optical grisms have not been extensively used before this campaign. Its grisms (175-520 nm) encompass known cometary fluorescence bands (e.g., CO2+, OH, CO, NH, CS, CN, etc.) that can quantify and track the water and organic ice chemistry in the coma. Until the scheduled repairs of HST's STIS, Swift is currently the sole space-borne observatory that could characterize the molecular composition of a comet at UV-optical wavelengths. By its rapid cadence it is perfectly suited to characterize changes in the temporal development and composition of released gas. We repeatedly observed Comet Tuttle from November 2007 to April 2008 with Swift's UV-Optical Telescope, providing a unique dataset that reveals variations in the comet's gas production rate on a scale of hours as well as months. We will discuss this variability in the context of the nucleus’ rotation and the comet's orbital motion around the Sun. References: [1] Mumma M.J. et al (1993) in Protoplanets and Planets III, Univ. Ariz. Press, 1177 [2] Gehrels N. (2004) Ap.J.611, 1005- Publication:
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AAS/Division for Planetary Sciences Meeting Abstracts #40
- Pub Date:
- September 2008
- Bibcode:
- 2008DPS....40.0505B