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THE ASTRONOMER Electronic Circular No 2636      2010 Apr 17 19.46UT
Ed:Guy M Hurst, 16,Westminster Close, Kempshott Rise,  Basingstoke,
Hants, RG22 4PP,England.Telephone/FAX(01256)471074Int:+441256471074
INTERNET: GUY@TAHQ.DEMON.CO.UK      Backup: gmh@wdcc1.bnsc.rl.ac.uk
WORLD WIDE WEB                         http://www.theastronomer.org
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S DORADUS
Noel D. Richardson, Georgia State University reports on Astronomer's 
Telegram 2560:

S Dor is a prototypical Luminous Blue Variable and is one of the 
brightest objects in the Large Magellanic Cloud.  The star's photometric 
history over the last century is described by van Genderen et al. (1997) 
in terms of a very-long-term and a quasi-periodic (7 year) variation. 
The faintest V-magnitude (V=11.3) was observed in 1965, while the 
brightest V-magnitude (V=8.8) was observed in 2006 by the All Sky 
Automated Survey (ASAS).  The star is currently fading in brightness.

We are obtaining spectroscopic observations of S Dor with the CTIO 1.5 m 
telescope and RC spectrograph. We began an H-alpha spectroscopic survey 
of this and other bright LBVs two years ago, and we generally obtain a 
spectrum every 2-3 weeks.  We now have collected a total of 28 spectra 
of S Dor.

The H-alpha emission line equivalent width of S Doradus exhibited only a 
modest increase over the first 1.5 years, but during the last eight 
months the emission has tripled in strength. The fast increase of the 
H-alpha emission was preceded by a fading in the V-band flux. The ASAS 
photometry data show that the star is now fainter than at any time over 
the last nine years.  Current AAVSO CCD observations indicate that the 
magnitude has reached V=9.83 (2010 Mar 08). The current event offers us 
the first opportunity in over a decade to explore this unusual state of 
S Dor.

SUPERNOVA 2010T IN ANONYMOUS GALAXY
Discovery by the CHASE Project of a possible supernova (CBET 2159):
SN      2010 UT      R.A.  (2000.0)  Decl.    Mag.     Offset
2010T   Jan 25.30   13 14 47.88  -15 58 24.8  18.2    1.9"E,  2.3"S

SUPERNOVA 2010U IN NGC 4214
Discovery by Koichi Itagaki of a possible supernova (CBET 2161):
SN      2010 UT      R.A.  (2000.0)  Decl.    Mag.     Offset
2010U   Feb  5.63   12 15 41.06  +36 20 02.9  16.0   20"  E, 27  "N

SUPERNOVA 2010V IN PGC 51710
Discovery by Pavel Balanutsa of a possible supernova (CBET 2162):
SN      2010 UT      R.A.  (2000.0)  Decl.    Mag.     Offset
2010V   Feb  4.06   14 28 38.46  +30 38 39.5  14.3R   1  "W,  4.5"S
Images of 2010V have been posted at website URL 
http://observ.pereplet.ru/images/SN04feb10/SN100204.jpg

SUPERNOVA 2010W IN PGC 37549
Discovery by Berto Monard of a possible supernova (CBET 2165):
SN      2010 UT      R.A.  (2000.0)  Decl.    Mag.     Offset
2010W   Feb  7.07   11 56 48.07  -38 11 11.3  16.7   18  "E, 22  "N

SUPERNOVA 2010X IN NGC 1573A
Discovery by D. Rich of a possible supernova (CBET 2166):
SN      2010 UT      R.A.  (2000.0)  Decl.    Mag.     Offset
2010X   Feb  7.07   04 48 27.90  +73 28 14.8  16.7    4.4"E,  6.0"N

Guy M Hurst