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(cba:news) TY Vul and V1084 Her (RX1643+34) (Joe Patterson) [2010-06-22T20:10:19Z]


Dear CBAers,

Richard Sabo just sent me a night of data on TY Vul - clear, strong superhumps at a period about 2 hours. First time ever! Fire at will.

Lots of northern dwarf novae peppering the predawn summer sky. Best to pick one and stick with it, usually. I'll try to keep everyone posted on the ups and downs of each.

Speaking of which... two other stars I failed to report on a few days ago. A few of you (led by Bill Goff) have tackled our hardest target star, sdss 1339+48. Bill's observations do show the pulsations, which I wondered about. But they, along with the big-telescope data which preceded it, also show that the pulsations are not stable over baselines greater than a few days. In fact, I suspect that this is true of all the GW Lib stars. It means that long campaigns don't reap uniquely valuable rewards - revealing tiny rates of period change, for example. So let's put sdss1339 aside.

And for the same reason... let's resurrect V1084 Her = RX1643+34. I've now analyzed all 2010 data on this bright novalike - and was somewhat amazed to find the negative superhump at *exactly* the same frequency as in 2001. Generally one doesn't expect disk precession to show a good clock; none of the others do. So now this object is (somewhat) uniquely curious, and it's bright enough to be a good target for maybe 2 more months. Good northern evening target, or all night if you'd like a bright target. Try to use star #2 of Mickaelian et al. 2002 as your comparison (V=12.97).

V1084 Her is near V795 Her in brightness, coordinates, and reason to observe. You'll probably want to pick one or the other... but the more sure winner right now is V1084.

joe