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Special Notice #318: SN 2012hr, a Type Ia supernova prior to maximum

December 23, 2012: SN 2012hr was discovered by Peter Marples (Loganholme, QLD, Australia, Backyard Observatory Supernova Search (BOSS)) [not by Colin Drescher (Calamvale, QLD, Australia; BOSS) as originally reported in AAVSO Special Notice #318; Drescher reported Marples' discovery to CBAT as announced in CBET 3346] on 2012 December 16.53.  The object was discovered at a red magnitude of 14.8.  Subsequent spectroscopy by Milisavljevic et al. and Morrell et al. on December 19-20 indicate this object is a Type Ia supernova about one week before maximum light.  The object is well-placed outside of the majority of galaxian light of the presumed host, PGC 18880.  See CBET 3346 (D.W.E. Green, editor) for more details.

The object will likely be slightly brighter than 14.8 at the time of publication of this Special Notice.  Use of photometric filters is strongly encouraged by CCD observers, so that light curves may be more easily calibrated.  The supernova is located at the following (J2000) coordinates:

RA: 06 21 38.46, Dec: -59 42 50.6

A sequence is available for this supernova, and may be plotted using AAVSO VSP:

http://www.aavso.org/vsp

Please report all observations as "SN 2012hr".

This AAVSO Special Notice was prepared by M. Templeton.

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