Variable Star Photometry

New Variable Star Discovered

While doing photometry of a long period variable, SW UMa, for AAVSO, I also did the photometry for all the other stars in the field.  As it happens, I found one of the stars, GSC 3798:492, is a previously unknown variable.

The preliminary phased light curve below is complete in v and partial curves are shown in r and i. The portions of the light curve in r and i are shifted arbitrarily on the magnitude axis for now. They will be calibrated later. The magnitude axis is in v based on a nearby star’s AAVSO magnitude of 11.2. The comparison star had some variability and turned out to be a carbon star itself. The long period variability of the carbon star added small shifts to the photometry which were approximately subtracted out for this curve. The photometry will need to be redone from the original images using a comparison star that is not itself variable.

The light curve indicates this star is an RR Lyrae type. These stars pulsate and change color as they change size. The color change is evidenced by the different slopes and amplitudes of the v, r, and i curves. The color indices v-r and r-i change with time.