Comet C/2012 S1 (Ison)
Abstract
M. J. Mumma, M. A. DiSanti, L. Paganini, G. L. Villanueva, B. P. Bonev, E. L. Gibb, J. V. Keane, and K. J. Meech (a combined team from Goddard Space Flight Center, the University of Missouri at St. Louis, and the University of Hawaii) report preliminary abundances or upper limits for trace volatiles in comet C/2012 S1 based on NIRSPEC spectra obtained with the Keck II telescope on Oct. 22.6 and 24.6 UT (with the comet at r about 1.2 AU, Delta about 1.5 AU). Water-production rates on these dates were reported on CBET 9261. Based on an assumed rotational temperature of 50 K, the mean production rates (about 10**25 molecules/s) and mixing ratios for trace species are: CH_3OH (14 +/- 3; 1.1 +/- 0.3 percent), C_2H_6 (2.6 +/- 0.5 percent; 0.21 +/- 0.05 percent); CH_4 (7.6 +/- 3; 0.7 +/- 0.3 percent), CO (< 28; < 2.0 percent, 3-sigma), HCN (< 1.2; < 0.1 percent, 3-sigma).
- Publication:
-
International Astronomical Union Circular
- Pub Date:
- November 2013
- Bibcode:
- 2013IAUC.9263....2M