[IAUC] CBET 3245: 20121002 : COMET C/2012 S4 (PANSTARRS)
quai en eps.harvard.edu
quai en eps.harvard.edu
Mar Oct 2 08:28:17 ART 2012
Electronic Telegram No. 3245
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 en eps.harvard.edu (alternate cbat en iau.org)
URL http://www.cbat.eps.harvard.edu/index.html
Prepared using the Tamkin Foundation Computer Network
COMET C/2012 S4 (PANSTARRS)
Bryce Bolin, Larry Denneau, Richard Wainscoat, Rob Jedicke, Peter
Veres, and Marco Micheli report the discovery of a comet that appears
non-stellar in each of the two i-band and two r-band discovery exposures that
were obtained by the Pan-STARRS1 telescope (discovery observations tabulated
below); the full-width-at-half-maximum of star images in each exposure was
approximately 1".25, while the comet has a FWHM of approximately 2". After
posting on the Minor Planet Center's NEOCP webpage, other CCD astrometrists
have commented on the object's cometary appearance. P. Birtwhistle (Great
Shefford, Berkshire, England; 0.40-m f/6 Schmidt-Cassegrain reflector) found
the comet to appear distinctly diffuse with a 10" coma that is only moderately
condensed, though elongated slightly north-south with no tail visible, on
images from Sept. 29.1 UT; his follow-up exposures on Sept. 29.9 also show
a diffuse 10" coma with no tail. Stacked images taken by R. Holmes (Ashmore,
IL, USA; 0.81-m f/4 astrograph; measured by T. Vorobjov, L. Buzzi, and S.
Foglia) on Sept. 30.2 show a 10' coma. Images taken by J. D. Armstrong and M.
Micheli with 2.0-m f/10 "Faulkes Telescope North" at Haleakala on Sept. 30.3
show a definitely cometary appearance (FWHM of coma about 2".8 in 1".1 seeing,
but with no obvious tail in 800 s of total exposure time). H. Sato (Tokyo,
Japan; images taken remotely with a 0.43-m f/6.8 astrograph at the RAS
Observatory near Mayhill, NM, USA) writes that twelve stacked 60-s images
taken on Sept. 30.4 show a coma that was strongly condensed and 12" in
diameter. Images taken by G. Masi and F. Nocentini (Ceccano, Italy; 0.43-m
f/6.8 reflector; measured by G. Masi and U. Masi) on Sept. 30.9 show a 10"
coma.
2012 UT R.A. (2000) Decl. Mag.
Sept.28.41495 0 54 03.06 +60 18 16.0 19.3
28.42816 0 54 01.35 +60 18 09.4 19.3
28.44101 0 53 59.71 +60 18 02.9 19.2
28.45291 0 53 58.18 +60 17 56.6 19.3
The available astrometry, the following preliminary parabolic orbital
elements by G. V. Williams, and an ephemeris appear on MPEC 2012-T04.
T = 2013 June 29.5635 TT Peri. = 163.9611
Node = 173.1503 2000.0
q = 4.337831 AU Incl. = 126.5168
NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
superseded by text appearing later in the printed IAU Circulars.
(C) Copyright 2012 CBAT
2012 October 2 (CBET 3245) Daniel W. E. Green
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