Electronic Telegram No. 4137
Central Bureau for Astronomical Telegrams
Mailing address:  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/2015 P4 (PANSTARRS)
     R. Weryk and E. Lilly report the discovery of a comet in four w-band
exposures taken with the 1.8-m Pan-STARRS1 telescope at Haleakala on Aug. 14.5
UT (discovery observations tabulated below), noting evidence of a short tail
extending for approximately 6" in p.a. approximately 250 degrees.  Pre-
discovery Pan-STARRS1 observations were subsequently found also on July 24.

     2015 UT             R.A. (2000) Decl.       Mag.
     July 24.54456   23 40 32.93   -12 03 17.4   21.6
          24.55704   23 40 33.10   -12 03 19.5   21.7
          24.56947   23 40 33.27   -12 03 22.1   21.7
     Aug. 14.49513   23 41 43.45   -13 37 36.7   21.1
          14.50740   23 41 43.31   -13 37 40.8   21.0
          14.51963   23 41 43.19   -13 37 44.7   21.1
          14.53189   23 41 43.06   -13 37 48.8   21.0

After the object was posted on the Minor Planet Center's NEOCP webpage, A.
Maury and J.-F. Soulier obtained images with a 0.4-m f/8 Ritchey-Chretien
reflector at San Pedro de Atacama, Chile, on Aug. 19.24-19.31 UT that show an
8" coma and a curved tail 17" long in p.a. 270 deg; they measured red mag
19.6-19.8.  W. H. Ryan, Magdalena Ridge Observatory, found the comet to show
a tail toward p.a. about 250 deg on R-band images taken with the 2.4-m f/8.9
reflector on Aug. 19.3; he measured red mag 19.7-19.9.
     The available astrometry, the following elliptical orbital elements by
G. V. Williams, and an ephemeris appear on MPEC 2015-Q24.

                    Epoch = 2015 June 27.0 TT
     T = 2016 Jan. 18.6531 TT         Peri. = 280.6842
     e = 0.583374                     Node  = 104.7407  2000.0
     q = 2.526729 AU                  Incl. =   8.7125
       a =  6.064746 AU    n = 0.0659911    P =  14.9 years


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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2015 CBAT
2015 August 20                   (CBET 4137)              Daniel W. E. Green