Re: GSC 540-84

[Arne Henden <aah@nofs.navy.mil>]

These 2 points may be outside 3-sigma, but are not duplicated on other nights.
It is highly unlikely that the pulsational period would be locked
to an orbital period if this is an eclipsing system.  More likely is
that you have just underestimated your errors.  The displacement of
the Rc vs V light curves every so often is also troubling and
sounds like an instrumental/reduction error to me, or again an
underestimate of the errors.
Arne

Michael Koppelman wrote:
> More data here:
> 
> http://www.lolife.com/astronomy/gsc540-84/gsc540-84_color.jpg
> 
> Something peculiar is going on. Notice the two weird data points in the 
> V band at phase 1.15 or so. The images look perfectly good and don't 
> have errors or other indications of bad data. These points go up and 
> meet the other night of data. Both nights use the same comp star and 
> same everything else. The V band seems to have the same phenomena as the 
> Rc band in terms of the light curve being displaced a bit every so 
> often. The errors in the comp star magnitudes for the 8/22 data was 
> 0.002. It was a very steady night. Those two points are way outside even 
> 3-sigma. Seen anything like that before?
> 
> It is far-fetched speculation at this point, but could this be an 
> eclipsing RR Lyr star?
> 
> Cheers,
> Michael Koppelman
> 
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