IAU Electronic Telegram No. 4283

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 P/2016 GE_216 = P/2010 N1 (WISE)
     An apparently asteroidal object that was reported from CCD images taken
on 2016 Apr. 10 with the 1.8-m Pan-STARRS1 telescope at Haleakala (astrometry
tabulated below, together with earlier Pan-STARRS1 observations from Mar. 5
and Apr. 2), and was given the minor-planet desigation 2016 GE_216 when
published on MPS 701474, was noted by R. J. Wainscoat likely to be a comet
from its appearance on Pan-STARRS1 exposures taken on June 4.4 UT (when it
was noted to be at mag 19.1-19.3).  Wainscoat actually noted it as having a
slightly extended point-spread function (1".3, vs. 1".2 for nearby stars)
with a very faint tail to the southwest on four 45-s w-band exposures on
June 4, before he realized it as being 2016 GE_216.

     2016 UT             R.A. (2000) Decl.       Mag.
     Mar.  5.55407   15 37 25.91   + 3 03 48.1   21.7
           5.56566   15 37 26.73   + 3 03 51.0   21.8
           5.57727   15 37 27.58   + 3 03 53.6   21.6
           5.58898   15 37 28.45   + 3 03 56.5   22.1
     Apr.  2.53665   16 04 34.29   + 5 29 55.8   20.8
           2.54975   16 04 34.75   + 5 30 00.5   20.8
           2.57606   16 04 35.67   + 5 30 09.7   20.5
          10.58172   16 08 46.30   + 6 16 14.9   20.5
          10.59361   16 08 46.54   + 6 16 18.8   20.5
          10.60547   16 08 46.79   + 6 16 22.6   20.5
          10.61735   16 08 47.04   + 6 16 26.7   20.5

M. Micheli later wrote that three 60-s gri-filtered follow-up images taken at
Mauna Kea with the Canada-France-Hawaii Telescope on June 5.36 UT by Wainscoat
and P. Forshay show the comet to have a central point-spread function that
is starlike (about 0".8 FWHM) but with a weak wide tail extending at least
5" from the nuclear condensation at p.a. roughly 200 deg.
     After Wainscoat's report arrived on June 4, Erwin Schwab (Egelsbach,
Germany) reported his recovery of comet P/2010 N1 (cf. discovery announcement
on IAUC 9157) from CCD images obtained on June 5.1 UT by P. Ruiz with a 1.0-m
f/4.4 reflector at the European Space Agency's Optical Ground Station at
Tenerife (with measurement assistance by M. Micheli, D. Koschny, A. Knoefel,
and M. Busch), the comet being asteroidal in appearance on the 60-s exposures
(which are tabulated below).

     2016 UT             R.A. (2000) Decl.       Mag.   Observer
     June  5.07121   15 51 47.83   + 3 38 06.8   18.4   Ruiz
           5.07874   15 51 47.56   + 3 37 59.9   18.7     "
           5.08626   15 51 47.28   + 3 37 52.6   19.2     "

In a later report, Schwab reported the apparent identity with 2016 GE_216,
which was confirmed by G. V. Williams, Minor Planet Center.  The indicated
correction to the prediction by S. Nakano for P/2010 N1 in the ICQ's 2015
Comet Handbook (p. H15) is Delta(T) = -0.65 day.
     Additional astrometry for the 2016 apparition, the following linked
orbital elements by Williams (from 110 observations spanning 2010 Apr. 13-
2016 June 4; mean residual 0".3), and an ephemeris were published on MPEC
2016-L36.

                    Epoch = 2016 July 31.0 TT
     T = 2016 July 13.23045 TT        Peri. = 160.86057
     e = 0.4965603                    Node  = 106.10766 2000.0
     q = 1.6545582 AU                 Incl. =  15.36661
       a =  3.2865075 AU   n = 0.16542538   P =   5.96 years


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

                         (C) Copyright 2016 CBAT
2016 June 6                      (CBET 4283)              Daniel W. E. Green