(cba:news) AM CVn and T Pyx

[Joe Patterson]

Hi CBAers,

It's not exactly "news", but I just wanted to cheer-lead for two of our 
absolute favorite stars: AM CVn and T Pyx.  Both are in fine position 
for observing - T Pyx somewhat (but not much) toward the end of its 
prime season, and AM CVn somewhat (but not much)before the middle of its 
prime season.  Where "prime" means transiting at local midnight.

These two stars probably represent the end-states of most CVs: one 
spiralling out rapidly, the other spiralling in.  We're the only ones 
who really know this (sssshhhh...), so it's up to us to get these rates 
of in/out-spiral as accurately as we can.  Although we observe them a 
lot, it's always the latest data which has the highest weight in 
measuring these rates.  So I hope you'll give these stars a high 
priority in your March observing... and reward them with *long* nightly 
runs.

Just for your computing pleasure, I'm attaching a recent time series for 
these stars: a 5-day time series on AM CVn, and  9-day sequence on T 
Pyx.  Both a "zeroed" (mean subtracted), which aids in period-finding.
The Tpyx series is courtesy of Josch, Gordon, and Peter Nelson.  The AM 
CVn series is courtesy of David Cejudo, Tonny, Shawn Dvorak, Geoff 
Stone, ken menzies, and stephen brincat.  Try your period-finding 
routines on them.

joe
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