[IAUC] CBET 598: 20060823 : V723 CASSIOPEIAE

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                                                  Electronic Telegram No. 598
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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V723 CASSIOPEIAE
     J.-U. Ness and S. Starrfield, Arizona State University; G. Schwarz
and K. Vanlandingham, West Chester University; R. M. Wagner, LBT
Observatory; J. Lyke, Keck Observatory; C. E. Woodward, University of
Minnesota; D. K. Lynch, The Aerospace Corporation; J. Krautter,
Landessternwarte, Heidelberg-Koenigstuhl; and J. H. M. M. Schmitt,
Hamburger Sternwarte, report that four SWIFT XRT observations of V723
Cas (N Cas 1995) were obtained between July 9 and July 14 with a total
observing time of 8700 seconds.  The count rate was significantly lower
than in January 2006 (cf. IAUC 8676), declining from 0.024 counts/s in
January to 0.01-0.015 counts/s in July.  A Kolmogorov-Smirnov test detected
no significant difference in the spectral shape when compared to the
super-soft-source spectrum that was seen in January.  Preliminary blackbody
models reveal the same effective temperature of 312000 K but a smaller
radius.  The estimated bolometric luminosity is 2 x 10**(36) erg/s.  The
AAVSO visual light curve over the past year shows no significant long-term
variability exceeding about 0.2 mag (V approximately 15.0) although
short-term fluctuations appear to be present.  This nova has been bright
for more than 11 years, and the lower luminosity may indicate that nuclear
burning on the white dwarf is turning off.  Alternatively, renewed
accretion is maintaining a permanent, albeit highly variable,
super-soft-source state.  Continued monitoring at all wavelengths is urged.


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                         (C) Copyright 2006 CBAT
2006 August 23                   (CBET 598)               Daniel W. E. Green