The Volatile Composition of Comet Boattini (C/2007 W1) from Infrared Spectroscopy
Abstract
Comet Boattini (C/2007 W1) is a long-period (likely dynamically new) comet that was discovered on 2007 November 20 as part of the Mt. Lemmon Survey and reached perihelion on 2008 June 24.9 UT (q = 0.8495 AU). High-resolution spectra of Comet Boattini were obtained in May and July 2008, on six pre-perihelion dates (Rh = 1.23 - 0.966 AU) and three post-perihelion dates (Rh = 0.862 - 0.900 AU), using the near-IR echelle spectrographs CRIRES at the 8-m Antu telescope on Cerro Paranal, Chile and NIRSPEC at the 10-m Keck 2 telescope on Mauna Kea, HI. For the slit widths used, CRIRES delivers a spectral resolving power of 5 x 104, and NIRSPEC delivers 2.5 x 104.
Our observations targeted the usual suite of parent volatiles (H2O, C2H6, CH4, CH3OH, H2CO, CO, HCN, C2H2), with the goals of characterizing the chemistry of the comet and also searching for compositional changes with time. C2H6 was substantially enriched in Comet Boattini compared with its abundance in most Oort cloud comets observed to date, being similar to that measured in the split comet LINEAR (C/2001 A2), and in the Jupiter family comet 17P/Holmes following its outburst in October 2007. Meanwhile, the abundances of other parent volatiles were more closely in line with "normally” observed values. The most intriguing finding from our preliminary analysis is an apparent change in composition with time - the abundance of CH3OH increased with time while C2H6 and perhaps CO decreased with time. Results and implications for processing in the nascent solar system will be discussed. This work is supported by the NASA Astrobiology Program under RTOP 344-53-51, by the NASA Planetary Astronomy Program under RTOPs 344-32-30-07 and 344-32-98.- Publication:
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AAS/Division for Planetary Sciences Meeting Abstracts #40
- Pub Date:
- September 2008
- Bibcode:
- 2008DPS....40.0507D