(cba:news) Fwd: AM CVn and T Pyx

[Joe Patterson]

Sorry folks, I forgot the attachment.



-------- Forwarded Message --------
Subject: 	(cba:news) AM CVn and T Pyx
Date: 	Fri, 1 Mar 2019 12:46:18 -0500
From: 	Joe Patterson <jop at astro.columbia.edu>
Reply-To: 	cba-chat at cbastro.org
To: 	cba-news at cbastro.org




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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