Electronic Telegram No. 3686
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
CBAT Director:  Daniel W. E. Green; Hoffman Lab 209; Harvard University;
 20 Oxford St.; Cambridge, MA  02138; U.S.A.
e-mail:  cbatiau@eps.harvard.edu (alternate cbat@iau.org)
URL http://www.cbat.eps.harvard.edu/index.html
Prepared using the Tamkin Foundation Computer Network


COMET C/2012 S1 (ISON)
     N. Dello Russo, Applied Physics Laboratory (APL), Johns Hopkins
University (JHU); R. J. Vervack, Jr., APL, JHU; H. Kawakita, Kyoto Sangyo
University; A. Cochran, University of Texas; W. Harris, University pf Arizona;
H. Weaver, APL, JHU; H. Kobayashi, Kyoto Sangyo University; N. Biver, D.
Bockelee-Morvan, and J. Crovisier, Observatoire de Paris; E. Jehin, Universite
de Liege; and C. Lisse, APL, JHU, report production rates and relative
abundances for H_2O, C_2H_6, CH_3OH, and CH_4 in comet C/2012 S1 with high-
resolution infrared spectroscopy (R about 25000) using NIRSPEC at the Keck II
observatory.  Observations were obtained with NASA time on Oct. 28.6 UT, when
the comet's heliocentric and geocentric distances were r = 1.08 and Delta =
1.33 AU, respectively.  Assuming a gas rotational temperature of 50 K, which
is consistent with the relative intensities of the five detected H_2O lines,
the derived production rate for H_2O is (1.1 +/- 0.3) x 10**28 molecules/s.
Preliminary determinations of the relative abundances for CH_3OH, C_2H_6, and
CH_4 are 1.0 +/- 0.3 percent, 0.3 +/- 0.1 percent, and < 0.5 percent,
respectively, indicating that on this date the comet was somewhat depleted
in these species compared to other comets.


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2013 CBAT
2013 November 3                  (CBET 3686)              Daniel W. E. Green