Electronic Telegram No. 4298
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/2016 P2 (PANSTARRS)
     R. Wainscoat and E. Lilly report the discovery of another comet in four
w-band exposures obtained with the 1.8-m Pan-STARRS1 telescope at Haleakala
on Aug. 8 UT (discovery observations tabulated below, along with pre-discovery
Pan-STARRS1 observations identified later from July 9).  In each image on Aug.
8, the object shows a broad, low-surface-brightness tail extending to the
southwest for approximately 10"; the full-width-at-half-maximum of the nuclear
condensaton in a co-added image is 1".8, compared to 1".0 for adjacent stars.

     2016 UT             R.A. (2000) Decl.       Mag.
     July  9.57684   22 07 15.55   - 0 38 23.6   21.3
           9.58548   22 07 15.38   - 0 38 21.6   21.4
           9.59409   22 07 15.22   - 0 38 20.1   21.4
           9.60270   22 07 15.04   - 0 38 18.2   21.5
     Aug.  8.51832   21 52 03.08   + 0 06 42.1   21.0
           8.53101   21 52 02.57   + 0 06 41.8   21.1
           8.54373   21 52 02.04   + 0 06 41.6   20.9
           8.55649   21 52 01.52   + 0 06 41.6   21.0

After the comet was posted on the Minor Planet Center's PCCP webpage, other
CCD astrometrists have also commented on the object's cometary appearance.
Sixty co-added images taken by R. Holmes (Ashmore, IL, USA) with a 0.81-m f/4
astrograph at Westfield, IL, on Aug. 9.24-9.27 UT show a round 8" coma and a
narrow 21" tail in p.a. 235 deg, with the magnitude measured as 20.2-20.3;
additional co-added exposures taken on Aug. 12.2 by Holmes with a0.61-m f/4.5
astrograph at the same site show a compact 4" coma that is slightly elongated,
with a broad, 17".5 tail in p.a. 225 deg (magnitude 20.1-20.2).  H. Sato,
Tokyo, Japan, writes that sixteen stacked 60-s images taken with an iTelescope
0.61-m f/6.5 astrograph (+ luminance filter) located at the Sierra Remote
Observatory near Auberry, CA, USA, on Aug. 10.3 show the comet to be strongly
condensed with a coma 10" in diameter and not tail; the w-band magnitude was
19.8 as measured within a circular aperture of radius 5".0.  Thirty co-added
60-s exposures taken by P. Bacci, M. Maestripieri, and G. Carotta (with
measuring assistance by L. Tesi and G. Fagioli) using a 0.60-m f/4 reflector
at San Marcello Pistoiese, Italy, on Aug. 12.1 show a diffuse coma of
diameter 18"; the red magnitudes was given as 18.9-19.4.
     The available astrometry, the following elliptical orbital elements by
G. V. Williams, and an ephemeris appear on MPEC 2016-P120.

                    Epoch = 2015 Dec.  4.0 TT
     T = 2015 Nov. 16.5490 TT         Peri. = 352.1259
     e = 0.300261                     Node  = 283.3965  2000.0
     q = 3.109945 AU                  Incl. =  12.7575
       a =  4.444435 AU    n = 0.1051912    P =   9.37 years


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

                         (C) Copyright 2016 CBAT
2016 August 14                   (CBET 4298)              Daniel W. E. Green