-------------------------------------------------------------------
THE ASTRONOMER Electronic Circular No 2908      2013 Apr 22 18.13UT
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
-------------------------------------------------------------------
YY HERCULIS OUTBURST
U. Munari et. al., (INAF Padova-Asiago) report the symbiotic star YY Her 
in outburst. The previous outburst phase ended in 2006 with three 
brightness maxima in early 2003, mid-2004 and late 2005 with a 
separation of about 500 days among them.

The last of these maxima occurred on 2005 Nov 20 at B = 12.69, V=11.92, 
Ic=10.17.  After a flat quiescence period lasting six years, a new 
outburst phase begun in 2011.  A first maximum was reached on 2011 Dec 5 
at U=12.24, B=12.47, V=11.78, Rc=11.05 and Ic=10.16.  The current bright 
phase is the second maximum of the new outburst chain phase.

On 2013 April 15, at maximum brightness, they measured it at U=12.59, 
B=12.84, V=12.11, Rc=11.30, Ic=10.31.  Interestingly, the separation 
between these two recent maxima is again about 500 days, as it was for 
the chain of three maxima during the 2003-2005 outburst phase. This 
separation is shorter than the 590 day orbital period established from 
the reflection effect and the ellipsoidal modulation observed in 
quiescence.

SUPERNOVA 2013at (MASTER)
2013at  Mar 19.74   18 50 11.29  +30 20 59.5  16.9  11.9"W   15.1"S
Additional CCD magnitudes: Mar. 21.144, 17.5 (F. Luppi and L. Buzzi, 
Italy; 0.38-m reflector; position end figures 11s.23, 59".7)
Edo Berger: spectrum Mar. 21 indicates a type-II supernova. Four days 
after maximum.

SUPERNOVA 2013au (CSS)
2013au  Mar 23.25   12 21 14.16  +47 29 52.4  17.7            1  "N
Denis Denisenko, Sternberg Astronomical Institute (SAI), reports the 
independent discovery at mag 16.8 by P. Balanutsa on 60-s unfiltered 
MASTER-Amur survey images (limiting mag 17.9) obtained on Mar 28.480 UT 
with 0.40-m f/2.5 reflector.
J. Polshaw: spectrum Mar 30 normal type-Ia around maximum.

SUPERNOVA 2013av (CSS)
2013av  Mar  1.50   12 19 32.65  +38 02 25.9  17.7  51.8"W   21.2"S
L. Tomasella: spectrum Mar 16 type-Ia and similar to SN 1994D at about 
50 days after maximum light.

SUPERNOVA 2013aw IN PGC 91020 = PSN J10305847+2004529
2013aw  Mar 11.30   10 30 58.47  +20 04 52.9  20.3   6.5"E    2.1"S
L. Tomasella: spectrum Mar 15 suggest type-II a few days after explosion

SUPERNOVA 2013ax IN PGC 20704 (TNTS)
2013ax  Mar  7.64   07 20 03.51  +55 55 48.4  17.4   4.4"E    5.6"S
Jujia Zhang: spectrum Mar 10 type-Ia around maximum light

SUPERNOVA 2013ay IN IC 4745 (CHASE)
2013ay  Mar 26.29   18 42 37.86  -64 56 13.5  15.1  12.7"E   21.3"N
E. Y. Hsiao: spectrum April 1, type-Ia a few days past maximum.

Guy M Hurst