Electronic Telegram No. 4076
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 D6 (LEMMON-PANSTARRS)
     R. Weryk and E. Schunova, Institute for Astronomy, University of Hawaii,
report the discovery of another apparent comet in four w-band exposures taken
with the 1.8-m Pan-STARRS1 telescope at Haleakala on Mar. 16.5 UT (discovery
observations tabulated below); the object shows evidence of a tail extending
for approximately 5" towards position angle approximately 300 degrees.
Three additional w-band exposures taken on Mar. 17.5 again show evidence of a
faint tail, extending for approximately 5" towards p.a. approximately 270 deg.
Three 60-second follow-up CCD observations were obtained by R. Wainscoat and
M. Micheli using the Canada-France-Hawaii Telescope on March 17.3 (queue
observer D. Woodworth), showing the object as having a diffuse appearance and
an extended point-spread function (FWHM approximately 1".3, vs. 0".9 seeing
conditions measured on nearby stars on the same frames); there is also a
broad tail extending to the southwest of the nuclear condensation.
     Single-night apparently asteroidal observations (also tabulated below),
obtained on Feb. 27.4 UT with the 1.5-m reflector at Mount Lemmon by R. A.
Kowalski and R. G. Matheny, were then identified by G. V. Williams in Minor
Planet Center data; the object had been posted on the MPC's NEOCP webpage on
Feb. 27, but no additional observations were made as a result.

     2015 UT             R.A. (2000) Decl.       Mag.   Observer
     Feb. 27.41405   11 14 05.22   +31 07 30.1   19.9   Kowalski
          27.41848   11 14 05.05   +31 07 30.7   19.9     "
          27.42292   11 14 04.89   +31 07 31.5   20.2     "
          27.42735   11 14 04.75   +31 07 31.8   19.9     "
     Mar. 16.46774   11 04 16.02   +31 27 35.0   21.5   Pan-STARRS1
          16.47823   11 04 15.65   +31 27 34.8   21.7     "
          16.48881   11 04 15.29   +31 27 34.8   21.5     "
          16.49944   11 04 14.91   +31 27 34.9   21.5     "

After the comet was posted on the MPC's PCCP webpage, W. H. Ryan
(Magdalena Ridge Observatory 2.4-m f/8.9 reflector) reports that his R-band
CCD images taken on Mar. 17.2 UT show evidence of a small coma (mag 19.9-20.1)
and a faint, wide tail at p.a. about 225 deg.

     The available astrometry (including pre-discovery Mount Lemmon
observations from Mar. 9.3 UT, when the magnitude was given as 20.4-21.0), the
following preliminary elliptical orbital elements by Williams, and an ephemeris
appear on MPEC 2015-F31.

                    Epoch = 2015 June 27.0 TT
     T = 2015 July  7.4405 TT         Peri. = 124.7815
     e = 0.364819                     Node  =  46.2817  2000.0
     q = 4.574868 AU                  Incl. =  20.2018
       a =  7.202459 AU    n = 0.0509897    P =  19.33 years


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

                         (C) Copyright 2015 CBAT
2015 March 20                    (CBET 4076)              Daniel W. E. Green