Electronic Telegram No. 4102
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 P/2015 J3 (NEOWISE)
     An object found on infrared images taken with the Near-Earth Object
Wide-field Infrared Survey Explorer (or NEOWISE; formerly the WISE satellite;
astrometry tabulated below, with the optical-wavelength magnitude estimated)
has been found to be cometary by ground-based CCD astrometrists.

     2015 UT             R.A. (2000) Decl.       Mag.
     May  15.05651   21 40 29.55   -12 51 38.6    19
          15.18767   21 40 43.46   -12 51 11.5
          15.71281   21 41 38.57   -12 49 34.6
          15.84397   21 41 52.19   -12 49 09.7
          15.97525   21 42 05.92   -12 48 44.3
          16.04083   21 42 12.66   -12 48 33.8
          16.04096   21 42 12.76   -12 48 33.6
          16.10654   21 42 19.55   -12 48 22.2
          16.17211   21 42 26.37   -12 48 11.2
          16.30340   21 42 40.05   -12 47 47.5

After the object was posted on the Minor Planet Center's PCCP webpage, the
following reports have been received of cometary appearance.  R. A. Mastaler
writes that 120-s exposures taken on May 19.45-19.47 UT with the Spacewatch
1.8-m f/2.7 reflector (+ broadband Schott OG-515 filter) at Kitt Peak show a
diffuse tail about 5" long in p.a. 260-270 degrees; the magnitude was measured
to be 18.8-19.7.  H. Sato, Tokyo, Japan, reports that twelve stacked 60-s
exposures taken with an iTelescope 0.51-m f/6.8 astrograph (+ luminance filter)
near Mayhill, NM, USA, on May 20.4 show the object to have a moderately
condensed coma 12" in diameter but no tail; the w-band magnitude was 19.2 as
measured within a circular aperture of radius 6".5.
     The available astrometry, the following preliminary elliptical orbital
elements by G. V. Williams, and an ephemeris appear on MPEC 2015-K55.

     T = 2015 Mar.  4.3340 TT         Peri. = 129.6804
     e = 0.563313                     Node  = 111.5159  2000.0
     q = 1.498309 AU                  Incl. =   8.1344
       a =  3.431083 AU    n = 0.1550805    P =   6.36 years


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      superseded by text appearing later in the printed IAU Circulars.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 4102)              Daniel W. E. Green