A Photometric Variability Survey of Field K and M Dwarf Stars with HATNet

Understand

Using light curves from the HATNet survey for transiting extrasolar planets we investigate the optical broad-band photometric variability of a sample of 27,560 field K and M dwarfs selected by color and proper-motion.

• A total of 2120 stars exhibit potential variability, including 95 stars with eclipses and 60 stars with flares.
• Based on a visual inspection of these light curves and an automated blending classification, we select 1568 stars, including 78 eclipsing binaries, as secure variable star detections that are not obvious blends.
• We estimate that a further ~26% of these stars may be blends with fainter variables, though most of these blends are likely to be among the hotter stars in our sample.