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K. Magee-Sauer (Rowan Univ.), M.J. Mumma (NASA's GSFC), N. Dello Russo (CUA / NASA's GSFC), E.L. Gibb (NAS-NRC/NASA's GSFC), M.A. DiSanti (NASA's GSFC), B. Bonev (Univ. of Toledo/NASA's GSFC)
We present quantitative measurements of organic volatiles in comet C/2001 A2 (LINEAR) obtained with NIRSPEC at Keck-2 on Mauna Kea, using time awarded under a Target of Opportunity (TOO) proposal. The dates of observations were UT 2001 9 July, 10 July, 4 August, and 10 August. The NIRSPEC instrument is a cross-dispersed cryogenic infrared spectrometer that permits a nearly complete high-dispersion survey of the 2.9 - 3.7 \mum region. We detected numerous cometary molecules in A2, including H2O, C2H6, C2H2, CH4, HCN, CO, H2CO, CH3OH, NH2, and OH.
Comet A2 was noteworthy in that it shed six observable fragments during its perihelion passage. The objective of our TOO campaign was to search for chemical heterogeneity in the pre-fragmented comet by measuring the composition of various individual fragments. However, only the original component (B) was bright enough for detections during our post-perihelion observations. Our observations were taken immediately before and approximately one month after the fourth observed brightness outburst.
Preliminary analysis of our NIRSPEC data indicates that relative molecular abundances of several species differ between the July and August observing time periods. We also find that the relative abundances of volatile species are enriched relative to H2O for both the July and August observing runs.
KM-S would like to acknowledge support from the National Science Foundation RUI Program No. 0098411. This work was supported by the NASA Planetary Astronomy Program under RTOP 344-32-30-07 to MJM.
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Bulletin of the American Astronomical Society, 35 #4
© 2003. The American Astronomical Soceity.