Electronic Telegram No. 4174
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)
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Prepared using the Tamkin Foundation Computer Network


COMET C/2015 V4 (PANSTARRS)
     A comet has been found on CCD frames taken on Nov. 3.6 UT with the 1.8-m
Pan-STARRS1 telescope on Haleakala (discovery observations tabulated below),
although the faintness of the object on those images made it appear that it
could be either cometary or not real, according to R. J. Wainscoat, and so he
arranged for three confirming 60-s w-band exposures to be taken by C. Wipper
3.6-m Canada-France-Hawaii Telescope on Nov. 6.6.  The CFHT frames were
tracked at the predicted motion of the comet, and they showed that the object
is clearly cometary:  the nuclear condensation of the object has FWHM = 1".3
compared to adjacent stars that have FWHM perpendicular to the motion of the
object of 0".65, and in each image, a short-but-distinct tail is evident
extending to the west for approximately 5"; the red magnitude was measured to
be 19.6 (measured with M. Micheli).

     2015 UT             R.A. (2000) Decl.       Mag.
     Nov.  3.62455    7 25 03.38   -41 15 39.5   20.4
           3.63177    7 25 03.37   -41 15 42.8   19.9
           3.63898    7 25 03.45   -41 15 45.9   20.0

     After the object was posted on the Minor Planet Center's PCCP webpage,
other CCD astrometrists have also noted the object's cometary appearance.  H.
Sato, Tokyo, Japan, writes that twelve stacked 60-s exposures taken with an
iTelescope 0.51-m f/6.8 astrograph (+ luminance filter) at Siding Spring on
Nov. 7.6 UT show the comet to be strongly condensed with a coma 8" in
diameter with w-band magnitude 19.5 as measured within a circular aperture of
radius 4".9; no tail was detected.  A. Maury and T. Noel otbatined thirty-
eight unfiltered 120-s exposures with a 0.4-m f/8 Ritchey-Chretien reflector
at San Pedro de Atacama, Chile, on Nov. 13.3, which show cometary appearance
with FWHM = 3".9 compared to 3".0 for 20th-magnitude stars in the field.
     The available astrometry, the following preliminary elliptical orbital
elements by G. V. Williams, and an ephemeris appear on MPEC 2015-V167.

     T = 2016 July 29.5825 TT         Peri. = 303.2577
     e = 0.704821                     Node  = 180.6101  2000.0
     q = 5.556845 AU                  Incl. =  60.7018
       a = 18.825348 AU    n = 0.0120667    P =  81.68 years


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

                         (C) Copyright 2015 CBAT
2015 November 16                 (CBET 4174)              Daniel W. E. Green