(cba:news) introducing xss0056

Joe Patterson jop at astro.columbia.edu
Wed Nov 18 03:57:26 EST 2009

Dear CBAers,

Pardon me for exceeding the legal limit (for the chatters), but I wanted 
to promote a star I just started to observe last night.  That is 
XSS00564+4548... which I started in on after I saw that the CBAers were 
doing a fully adequate job with TT Ari from this longitude (western USA; 
we still ache for other longitudes).

This appears to be a DQ Her star with twin pulses around 8 and 8.5 
minutes, plus some signals at low-frequency (conjectured orbital, plus 
one other possibly around 30 minutes).  Pretty interesting.  It's plenty 
bright (around 14.8), and well placed for very long observation in 
Cassiopeia.  I have consecutive 8-hour nights on it, and am now begging 
for someone to carry the torch forward.  As in... well... this coming 
night, and thereafter.  Densely spaced long time series are precisely 
what's needed to enable great sensitivity in period searches.  The usual 
CBA routine - unfiltered light, 30-60 s exposures, find a comparison you 
like and stick with it - will do just fine.  There's a little companion 
roughly 10 arcsec east of the CV, at about 19th mag I think; probably 
not relevant unless the CV does something funny.  You can find a chart 
and some details in Bikmaev et al., astro-ph 0603715.

The TT Ari campaign rolls on, and has now picked up spectroscopy, UV 
(Galex), and X-ray (Swift - thanks Koji!) - to go along with the optical 
coverage.  It has been mostly in a "zero-accretion-light" state for a 
few days, with some little spits here and there.  There's an orbital 
hump in the light curve, yet the color is quite blue - so most likely 
it's hot WD + heated secondary.  It's strange: we love CVs because of 
their disks, but when the disks go away, then we're *really* interested.


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