Electronic Telegram No. 4142
Central Bureau for Astronomical Telegrams
Mailing address:  Hoffman Lab 209; Harvard University;
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Prepared using the Tamkin Foundation Computer Network


COMET P/2015 R2 (PANSTARRS)
     Richard Wainscoat and Eva Lilly report the discovery of a comet in four
45-s w-band exposures taken with the 1.8-m Pan-STARRS1 telescope at Haleakala
on Sept. 9.4 UT (discovery observations tabulated below), noting that the
object appears to be extended, though faint; a faint asymmetric extension
towards the northwest appears more apparent in the stacked image.

     2015 UT             R.A. (2000) Decl.       Mag.
     Sept. 9.41133   23 07 16.36   - 4 24 30.1   21.7
           9.42348   23 07 16.01   - 4 24 38.1   21.7
           9.43565   23 07 15.65   - 4 24 46.0   21.8
           9.44786   23 07 15.27   - 4 24 54.3   21.6

After the object was posted on the Minor Planet Center's PCCP webpage, H.
Sato, Tokyo, Japan, writes that sixteen 60-s exposures taken with an
iTelescope 0.51-m f/6.8 astrograph at Siding Spring on Sept. 11.6 UT show the
comet to be strongly condensed with a coma 6" in diameter and no tail; the
w-band magnitude was 19.9 as measured within a circular aperture of radius
6".6.
     The available astrometry, the following preliminary elliptical orbital
elements by G. V. Williams, and an ephemeris appear on MPEC 2015-S01.

     T = 2015 July  3.5731 TT         Peri. = 151.6355
     e = 0.418263                     Node  = 169.3747  2000.0
     q = 2.131279 AU                  Incl. =  10.9375
       a =  3.663648 AU    n = 0.1405508    P =   7.01 years


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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2015 CBAT
2015 September 16                (CBET 4142)              Daniel W. E. Green