[Aavso-photometry] CSS 081231..... (Peter Armstrong)

[Peter Armstrong]

James Roe wrote:

>I was looking forward to watching it re-emerge but from one
>image where it wasn't visible to the next it reappeared at "full" strength.
>Checking my measurements later, the star brightened just over 3 mags in
>under 25 seconds.

Actually its better than that!  I've been doing time series of this star since 
January, and have stumbled upon the same phenomenon.   The steep rise 
at the end of the deep eclipse seems to vary with each event - sometimes
taking two to three minutes to go from near nothing to full brightness, and
occasionally happens in consecutive exposures - in my case 30 second 
exposures with 5 seconds download time.

 From both of our data we can conclude that the star brightened fully during
the 5 seconds between shots - not just over a 25 or 35 second period.
The back-to-back full-off to full-on data points exclude a transition taking 
more than the 5 seconds between integrations.  It is lucky timing to catch 
the transition during a short window.

This fast rise will have to be explained in any proposed model of this 
unusual system.

Peter Armstrong (ACP)