Comet C/2012 X2 (Panstarrs)
Abstract
Henry Hsieh, Larry Denneau, Marco Micheli, Bryce Bolin, and Peter Veres Institute for Astronomy, University of Hawaii, report the discovery of a comet on two g-band 43-s exposures and two r-band 40-s exposures taken with the Pan-STARRS1 telescope on Haleakala (discovery observations tabulated below); the object is extended with a faint tail spanning p.a. 90-140 deg. After posting on the Minor Planet Center's NEOCP webpage, numerous other CCD astrometrists have also commented on the object's cometary appearance. H. Sato (Tokyo, Japan; obtained remotely with a 0.43-m f/6.8 astrograph at the iTelescope Observatory near Mayhill, NM, U.S.A.; Dec. 13.24-13.25 UT) notes that twelve stacked 60-s exposures show a strongly condensed, round coma 10" in diameter with total V-band magnitude 18.9 as measured within a circular aperture of radius 5".7. William H. Ryan (Magdalena Ridge Observatory; 2.4-m f/8.9 reflector; Dec. 13.3) finds a distinct coma of red mag 18.2 and tail in p.a. about 315 deg on four R-band images. D. J. Tholen writes that images obtained by M. Micheli and G. T. Elliott with the 2.24-m University of Hawaii reflector at Mauna Kea on Dec. 13.5-13.6 show an asymmetric coma and a tail extending as much as 40" to the northwest. Forty-five co-added 30-s images taken by T. Linder and R. Holmes with a 0.41-m f/11 Ritchey-Chretien reflector at Cerro Tololo on Dec. 14.2 show a round coma of diameter 4".5; their subsequent set of similar stacked images on Dec. 15.2 show a coma of size 4" x 6" elongated toward p.a. 250 deg, with a 3" tail in p.a. 310 deg. T. Lister reports that five stacked 300-s images taken with a 1.0-m f/8 Ritchey-Chretien reflector (Las Cumbres Observatory Global Telescope) at Cerro Tololo on Dec. 14.3 in 1".5 seeing show a central condensation with a coma of size about 5" and a tail about 30" long in p.a. 135 deg. Forty-five stacked 60-s exposures taken by R. Holmes (Ashmore, IL, USA; 0.61-m f/4 astrograph; Dec. 14.3; purportedly measured by four different people -- L. Buzzi, H. Devore, S. Foglia, and T. Vorobjov) show a coma of size 8" x 12", elongated in p.a. 310 degrees with a tail 30" long toward that position angle. Detlef Koschny, European Space Agency (ESA), Noordwijk, writes that images taken on Dec. 15.95-15.96 with a 1.0-m f/4.4 reflector at the ESA Optical Ground Station, Tenerife, by P. Ruiz (measured by Koschny, M. Busch, A. Knoefel, and E. Schwab) shows the comet to be elongated with a 10" tail in p.a. 300 deg. 2012 UT R.A. (2000) Decl. Mag. Dec. 12.52892 7 43 03.66 + 6 29 07.9 20.0 12.54241 7 43 03.35 + 6 29 03.0 20.0 12.55557 7 43 03.04 + 6 28 58.4 19.6 12.56790 7 43 02.75 + 6 28 54.0 19.6 The available astrometry, the following preliminary parabolic orbital elements by G. V. Williams, and an ephemeris appear on MPEC 2012-X104. T = 2013 Oct. 29.9103 TT Peri. = 244.2691 Node = 273.7298 2000.0 q = 4.374599 AU Incl. = 38.0016
- Publication:
-
Central Bureau Electronic Telegrams
- Pub Date:
- December 2012
- Bibcode:
- 2012CBET.3343....1S