We propose to obtain a short X-ray observation of the recently
discovered outbursting star in Cassiopeia ("Var Cas 2006"). The
quiescent counterpart appears to be a distant (1 Kpc) B star, and the
4 magnitude outburst is by far the largest ever seen in such a star.
This could be the signature of an accreting compact star in a close binary,
or it could be an extremely violent ejection of a shell by the B star
which has oddly failed to show emission lines at any time in its
history. The first scenario would produce a strong hard X-ray source
-- probably >0.5 UFU -- while the second would produce only soft X-rays
or none at all. A short observation with Swift would easily distinguish
between these.
Exact 2000 coords: 00 09 21.98 from Tycho-2 astrometry
+54 39 43.9
V= 7.4 in outburst Oct 30, =9.5 on Nov 2, probably 11.6 by about Nov. 9.