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Z CamPaign Update

posted Aug 10, 2010, 3:23 AM by Mike Simonsen   [ updated Sep 27, 2010, 6:44 PM ]
August 10, 2010

V391 Lyrae-

The most recent outburst may have been an inside out outburst. Its profile is different than the prior outbursts, with a relatively slow rise to maximum. This is fairly common in SS Cyg and other UGSS. The peak level reached in successive outbursts appears to be trending downward also. If the minimum magnitudes between outbursts trend upwards this could begin to resemble the 'damping down' look of many UGZs as they head into a standstill. I remain skeptical of V391 Lyr's membership in the Z Cam club, but she is an interesting star, well placed for the next several months, so I plan to stay on top of this one.

It is plain to see that the additional intense coverage of this star by CCD observers able to follow the entire cycle has already led to some interesting results.

EM Cygni-
The 'damping down' effect approaching standstill is evident in this 200 day light curve of EM Cyg. Successive outbursts gradually run out of steam, and the star enters a standstill. No doubt about this star's classification as a UGZ. It is also an eclipsing system, one of only two known UGZs to be eclipsers.

Z Cam-
The prototype of its class, Z Cam has also entered into standstill in the last couple weeks.

IW And-
After the seasonal gap in coverage, IW And appears to be exhibiting the same strange quasi-periodic behavior from last season. Keep the data coming!

V513 Cas-

IW Andromdae's kissin' cousin, V513 Cas, is also continuing this very eclipse-like behavior. I think we may have a new type of CV here, so I'm going to christen them the "IW Andromedae" stars until someone proves me wrong.