[IAUC] IAUC 9238: C/2011 U3; C/2009 P1 [25139-2012/04-R1]

[quai en eps.harvard.edu]

                                                  Circular No. 9238
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
New postal address:  Hoffman Lab 209; Harvard University;
 20 Oxford St.; Cambridge, MA  02138; U.S.A.
CBATIAU en EPS.HARVARD.EDU           ISSN 0081-0304
URL http://www.cbat.eps.harvard.edu/index.html
Prepared using the Tamkin Foundation Computer Network


COMET C/2011 U3 (PANSTARRS)
     As first announced on CBET 2878, L. Denneau, R. Wainscoat, and
H. Hsieh report the discovery of a marginally active comet on CCD
images taken with the "Pan-STARRS 1" 1.8-m telescope at Haleakala
(discovery observations tabulated below; physical details given on
CBET 2878).

     2011 UT             R.A. (2000) Decl.       Mag.
     Oct. 24.54384    3 37 16.15   +22 56 22.1   21.8
          24.58950    3 37 11.63   +22 55 42.2   21.9

The initial astrometry was published on MPEC 2011-U107; revised
osculating orbital elements by G. V. Williams from MPEC 2011-V31:

                    Epoch = 2012 June  2.0 TT
     T = 2012 June  4.8133 TT         Peri. = 289.7548
     e = 0.978650                     Node  = 228.3849  2000.0
     q = 1.039600 AU                  Incl. = 115.9257


COMET C/2009 P1 (GARRADD)
     L. Paganini and M. J. Mumma, Goddard Space Flight Center (GSFC);
M. Lippi, Max Planck Institute for Solar System Research (MPS); G.
L. Villanueva, GSFC; H. Boehnhardt, MPS; and B. P. Bonev and M. A.
DiSanti, GSFC, report the detection of parent volatiles in comet
C/2009 P1 on 2011 Sept. 17-21 UT (when r = 2.0 AU, Delta = 1.5 AU,
geocentric velocity = +19 km/s) using high-resolution infrared
spectra acquired with CRIRES at the European Southern Observatory's
Very Large Telescope.  The slit was oriented along the sun-comet
line.  They targeted thirteen volatile species:  H_2O, OH* (prompt
emission), CO, C_2H_6, CH_3OH, HCN, CH_4, OCS, C_2H_2, NH_2, NH_3,
H_2CO, and HDO.  Preliminary (nucleus-centered) results for the
mean production rates, rotational temperatures, and abundance
ratios (in percent, relative to water) are as follows:  H_2O, 9
lines, 5.1 +/- 0.7 x 10**28 molecules/s, 65 +/- 7 K, 100 percent;
CO, 8 lines, 6.7 +/- 0.4 x 10**27, 57 +/- 5 K, 13; C_2H_6, 4
Q-branches, 5.4 +/- 0.2 x 10**26, 55 +/- 10 K, 1.1; CH_3OH, 18
lines, 2.9 +/- 0.3 x 10**27, 54 +/- 9 K, 5.6; HCN, 10 lines, 2.1
+/- 0.6 x 10**26, 58 +/- 3 K, 0.41; CH_4, 2 lines, 8.3 +/- 2.1 x
10**26, 60 K (assumed), 1.6.  (Note that the total production rates
above are expected to be larger once the slit losses are corrected.)
Additional trace species are under evaluation.  The high fractional
abundance of CO suggests that C/2009 P1 is a CO-rich comet (similar
to C/1995 O1, C/1996 B2, and C/1999 T1).

                      (C) Copyright 2011 CBAT
2011 November 9                (9238)            Daniel W. E. Green