Re: GSC 1040-399 + new variable

[Michael Koppelman <lolife@bitstream.net>]

I opened this up in TS and fit a 30th order polynomial to it. It looked 
sine wave-ish. I grabbed the times of the maxima and calculated the 
difference. The average was 0.0463 with a std dev of 0.003. The I ran 
the Fourier on it and it found a strong period at 0.0478. There is a 
ton of noise in it but the data does phase somewhat convincingly at 
that period. It phases even more convincingly at twice that period at 
0.0956.

These two periods are 67 minutes and 133 minutes respectively. My 
exposures were every 186 seconds or so. It doesn't appear that this is 
an alias, but I guess I wouldn't know. My period error is at a much 
shorter interval so if the aperture was moving around due to something 
periodic like that, you'd think the signal would be closer to that 
time, which is I think 8 minutes or something. Those are the only two 
things I can thing of off the top of my head that could be me 
introducing a periodic error.

So I guess I would conclude that the data has a periodic signal in it. 
This could be actual variation or just errors I don't know about, 
perhaps relating to the companion that 2MASS can see about 5" away 
(which John Greaves pointed out). There is no sign of that star in my 
data. The amplitude on this is miniscule, around 0.04 or so, so I guess 
anything is possible.

Cheers,
Michael Koppelman


On Wednesday, July 16, 2003, at 10:56 AM, Arne Henden wrote:

> By eye, it looks like it might be periodic,
> which is good; periodic and low amplitude often indicates delta-scuti.
> Color information might help in the identification.