COMET P/2013 CE_31 (MOSS)
An apparently asteroidal object discovery reported by Claudine Rinner
(discovery observations tabulated below) on CCD images taken with a 0.5-m f/3
reflector in the course of the Morocco Oukaimeden Sky Survey (MOSS; cf. CBET
3020) -- and assigned the minor-planet designation 2013 CE_31 on MPS 454006
(published Feb. 17) by the Minor Planet Center, with initial orbits appearing
on MPEC 2013-C43 and 2013-C46 (the "Daily Orbit Updates" for Feb. 10 and 11)
-- has been found to show cometary appearance by other CCD astrometrists. An
independent discovery by Richard Wainscoat and Larry Denneau, University of
Hawaii, on images taken on Feb. 9 UT with the 1.8-m Pan-STARRS1 telescope (+
w filter) at Haleakala, was noted along with the presence of a tail > 1' long
in p.a. approximately 290 degrees; follow-up r-band images taken by Marco
Micheli and Wainscoat using the Canada-France-Hawaii Telescope at Mauna Kea
on Feb. 10 (queue observer Peter Forshay) show an extended nuclear
condensation, while three stacked images show the tail exending approximately
60" from the condensation in p.a. 290 deg. J. Scotti (Lunar and Planetary
Laboratory, University of Arizona) writes that mosaic images taken by T. H.
Bressi with the Spacewatch 0.9-m f/3 reflector at Kitt Peak on Feb. 17.2
show a 9"-long tail in p.a. about 275 deg. Scotti adds that subsequent
co-added images taken by R. S. McMillan, M. L. Terrenzoni, and himself on
Feb. 17.3 with the Steward Observatory 2.3-m Bok telescope show a coma
diameter of 7".0 and a narrow tail that extends 1'.67 in p.a. 285 degrees.

2013 UT R.A. (2000) Decl. Mag. Observer
Feb. 5.11210 10 25 19.50 +15 40 21.8 20.3 Rinner
5.12268 10 25 19.10 +15 40 23.7 20.2 "
5.13316 10 25 18.81 +15 40 26.4 20.1 "
5.14390 10 25 18.40 +15 40 29.0 19.5 "
6.15171 10 24 46.84 +15 44 21.1 20.1 "
6.16249 10 24 46.37 +15 44 23.2 20.4 "
6.17299 10 24 46.05 +15 44 26.0 20.5 "
6.18348 10 24 45.69 +15 44 28.3 20.0 "
6.19400 10 24 45.34 +15 44 30.7 20.5 "

The available astrometry (including prediscovery Spacewatch observations
from Jan. 19), the following elliptical orbital elements by G. V. Williams,
and an ephemeris appear on MPEC 2013-D23.

T = 2012 May 21.68047 TT Peri. = 27.76370
e = 0.1698669 Node = 87.15101 2000.0
q = 4.0228047 AU Incl. = 4.72318
a = 4.8459758 AU n = 0.09239154 P = 10.67 years

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superseded by text appearing later in the printed IAU Circulars.

(C) Copyright 2013 CBAT
2013 February 17 (CBET 3418) Daniel W. E. Green