Electronic Telegram No. 3991
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 P/2014 S4 (GIBBS)
     A. R. Gibbs reports his discovery of a comet on CCD images taken with the
Catalina Sky Survey's 0.68-m Schmidt telescope (discovery observations
tabulated below), the object described as faint, 10" in size but nearly
stellar, with a narrow tail in p.a. 270 deg, as seen on four co-added 30-s
unfiltered exposures obtained in good seeing.  Four co-added 60-s follow-up
exposures by Gibbs with the Mt. Lemmon 1.5-m reflector on Sept. 25.3 UT in
good seeing show a tail 20" long that fans from p.a. 280 to 270 deg, with a
slightly elliptical coma having FWHM size that is nearly double that of a
nearby star of similar magnitude.

     2014 UT             R.A. (2000) Decl.       Mag.   Observer
     Sept.24.31464    1 15 50.36   -11 48 01.7   19.5   Gibbs
          24.32167    1 15 50.02   -11 48 04.1   19.6     "
          24.32871    1 15 49.73   -11 48 07.6   19.0     "
          24.33573    1 15 49.35   -11 48 10.3   19.2     "

After the object was posted on the Minor Planet Center's PCCP webpage, H. Sato
(Tokyo, Japan) writes that ten stacked 60-s CCD exposures taken with an
iTelescope 0.51-m f/6.8 astrograph (+ luminance filter) at Siding Spring on
Sept. 26.54 shows an almost-stellar head (with w-band magnitude 19.2 as
measured within a circular aperture of radius 6".5) and a hint of a tail 5"
long toward p.a. 270 degrees.
     The available astrometry (including pre-discovery Catalina observations
from Sept. 14.4 with the object at mag 19.9-20.4), the following elliptical
orbital elements by G. V. Williams, and an ephemeris appear on MPEC 2014-S115.

     T = 2014 Sept. 9.1062 TT         Peri. = 257.3844
     e = 0.237049                     Node  = 106.0701  2000.0
     q = 2.395599 AU                  Incl. =  10.9573
       a =  3.139914 AU    n = 0.1771444    P =   5.56 years


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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2014 CBAT
2014 September 27                (CBET 3991)              Daniel W. E. Green