Electronic Telegram No. 4105
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
CBAT Director:  Daniel W. E. Green; 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 C/2015 K1 (MASTER)
     Vladimir M. Lipunov, Sternberg Astronomical Institute, Lomonosov Moscow
State University; David Buckley, South African Astronomical Observatory
(SAAO); and Denis Denisenko, Sternberg Astronomical Institute, Moscow State
University, report the discovery of a comet with a coma diameter of about 14",
elongated toward the west, on 60-s unfiltered survey images taken with the
"Mobile Astronomical System of the Telescope-Robots" (MASTER) auto-detection
system (double 0.40-m f/2.5 reflector) at the SAAO (discovery observations
are tabulated below).  The object was flagged by the auto-detection software
as one of 30-50 candidates that might be real moving objects from that night
(May 16/17 UT) for manual checking; after checking about 25 candidates, most
of which were noise on images, Denisenko found that this particular object
appeared real with a diffuse appearance, noting it to be a possible comet
with a coma diameter of about 14", he notified the Central Bureau, the Minor
Planet Center, and other observers.  The three discovery images are posted
at URL http://master.sai.msu.ru/static/comets/M504DRx-MASTER-SAAO-anim.gif.

     2015 UT             R.A. (2000) Decl.       Mag.
     May  17.14003    0 19 57.82   - 6 59 49.1   16.3
          17.14443    0 19 58.05   - 6 59 46.7   16.5
          17.14885    0 19 58.30   - 6 59 44.6   16.6
          18.13711    0 20 51.76   - 6 50 35.9   16.6
          18.13853    0 20 51.67   - 6 50 35.1   16.9
          18.14029    0 20 51.91   - 6 50 32.8   16.3
          18.14098    0 20 51.98   - 6 50 33.3   16.2

After the object was posted on the MPC's PCCP webpage, other CCD astrometrists
also have commented on the object's cometary appearance.  A. Maury and J.-F.
Soulier find that images taken on May 20.4 UT with a 0.4-m f/8 Ritchey-Chretien
reflector at San Pedro de Atacama, Chile, show a 28" coma and a 45" diffuse
tail spanning p.a. 195-260 deg (strongest tail at p.a. 230 deg); Maury and T.
Noel obtained follow-up images on May 22.34-22.37 that show a 20" coma.  C.
Jacques, E. Pimentel, and J. Barros obtained three stacked 60-s images on
May 22.3 with a 0.45-m f/2.9 reflector at the SONEAR Observatory, Oliveira,
Brazil, that show a condensed coma 30" in diameter.
     The available astrometry, the following preliminary parabolic orbital
elements by G. V. Williams, and an ephemeris appear on MPEC 2015-K70.

     T = 2014 Oct. 15.5449 TT         Peri. = 281.6804
                                      Node  =   5.3263  2000.0
     q = 2.608532 AU                  Incl. =  29.2996


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

                         (C) Copyright 2015 CBAT
2015 May 23                      (CBET 4105)              Daniel W. E. Green