Electronic Telegram No. 4230
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/2015 Y2 = P/2010 V1 (IKEYA-MURAKAMI)
     R. Weryk and R. J. Wainscoat report the discovery of another comet in
four r-band exposures taken with the 1.8-m Pan-STARRS1 telescope on Haleakala
(the Dec. 31 discovery observations tabulated below), the object described as
possibly extended but very faint.  Three follow-up 60-s w-band exposures
taken by Wainscoat and L. Wells with the 3.6-m Canada-France-Hawaii Telescope
on Jan. 1.5 UT confirm that the object is extended (magnitude 20.0-20.1) with
a very broad, low-surface-brightness tail extending in p.a. approximately 240
degrees (measured by M. Micheli with Wainscoat and Weryk).

     2015 UT             R.A. (2000) Decl.       Mag.
     Dec. 31.52127    9 11 27.63   +35 54 00.2   20.8
          31.53266    9 11 27.76   +35 54 03.4   20.8
          31.54396    9 11 27.89   +35 54 05.9   20.8
          31.55522    9 11 28.02   +35 54 08.9   20.6

Micheli and Wainscoat found a second cometary object on the CFHT images that
is moving with similar motion to the above object, though +92" in R.A. and
-44" in Decl. away; it shows a tail about 20" long in p.a. around 290 deg,
and the red magnitude is 20.7-20.9 (so somewhat fainter than the first
component).
     The first object above, designated comet 2015 Y2, was picked up in
Minor Planet Center automated software routines as being perhaps identical
with comet P/2010 V1 (cf. IAUCs 9175, 9176, 9183, 9189); this suggested
link was also made by Hidetaka Sato (Tokyo, Japan; communicated via S.
Nakano, Sumoto, Japan), who also suggested relation of the second component
(still awaiting confirmation while posted on the MPC's NEOCP webpage) with
the first.
     The indicated correction P/2015 Y2 to the prediction by G. V. Williams
for P/2010 V1 on MPEC 2013-O31 is Delta(T) = +7.2 days; the indicated
correction to the prediction by S. Nakano in the ICQ 2015 Comet Handbook (p.
H13) is Delta(T) = +7.0 days.  The available astrometry, the following
linked orbital elements by Williams (from 444 observations spanning 2010
Nov. 3-2011 Jan. 22; mean residual 0".7), and an ephemeris appear on MPEC
2016-A10.

                    Epoch = 2016 Apr.  2.0 TT
     T = 2016 Mar. 17.30143 TT        Peri. = 152.45530
     e = 0.4904120                    Node  =   3.78311 2000.0
     q = 1.5729883 AU                 Incl. =   9.38727
       a =  3.0867846 AU   n = 0.18173751   P =   5.42 years


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

                         (C) Copyright 2016 CBAT
2016 January 3                   (CBET 4230)              Daniel W. E. Green