Electronic Telegram No. 1203
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
CBAT@CFA.HARVARD.EDU (science)
URL http://www.cfa.harvard.edu/iau/cbat.html


HT CASSIOPEIAE
     E. O. Waagen, AAVSO, reports that the eclipsing SS Cyg-type dwarf nova
HT Cas is in outburst for the first time since Feb. 2002.  The outburst was
reported to the AAVSO by G. Chaple (Townsend, MA, U.S.A.), who observed it
at visual magnitude 13.6 on Jan. 10.0076 UT.  M. Uemura and colleagues at
Hiroshima University confirmed the outburst, giving mag V = 14.02 on Jan.
10.528 (communicated to the AAVSO via a "vsnet" alert message).  The star
was not visible to limiting mag 13.9 on Jan. 8.0, according to J. E. Bortle,
Stormville, NY, U.S.A.  This outburst looks to be a normal, brief outburst --
probably lasting only 2-3 days.  HT Cas, with an orbital period of 0.073647
day, shows deep eclipses, on the order of 1-2.5 magnitudes.  Other
observations of the current outburst reported to the AAVSO include a magnitude
estimate of 13.3 by J. Ripero (Madrid, Spain) on Jan. 10.7917, and 213
unfiltered CCD observations by J. Shears (Bunbury, Cheshire, England) made
during Jan. 10.814-10.972 that show HT Cas to be varying in eclipse at
magnitudes between approximately 14.2 and 16.9.
     This star, which varies between mag 16 and 19.5 in quiescence, has an
irregular history of outbursts.  According to observations in the AAVSO
International Database, all but one from 1979 to date have been brief and have
reached maximum brightness between 12.3 and 13.3 -- occurring in Jan. 1979,
Mar. 1980, Aug. 1985, Feb. 1987, Nov. 1989, Nov. 1995 (cf. IAUC 6264), Mar.
1997, Mar. 1998, July 1999, Apr. 2001 (possible outburst), Feb. 2002, Apr.
2003 (possible outburst, single observation).  On 1985 Jan. 12, HT Cas had a
bright, long outburst, reaching visual mag 10.7 and remaining brighter than
15.2 until Jan. 24 (cf. IAUC 4027, 4037).


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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2008 CBAT
2008 January 11                  (CBET 1203)              Daniel W. E. Green