Four New δ Scuti Pulsators from a Variability Survey of 131 Stars

In a photometric variability survey of 131 stars with B . 14 mag, we have found four new δ Scuti stars. We were sensitive to oscillation amplitudes as low as a few mmag. The detection rate of short-period (P < 0.1 d) pulsating variable stars, which may be relevant for planned large variability surveys such as GAIA, POI, and even the LSST, was therefore 3%. All four new variable stars have low pulsation amplitude (tens of mmag), and one has a very short period (0.0198 d). This star is one of the fastest known δ Scuti pulsators. The short period of this variable star makes it observationally tractable, and it may therefore be a particularly good candidate for asteroseismological studies. All four new variable stars will add to the cadre of low-amplitude and relatively short-period δ Scuti stars that are potentially useful for learning about the structure of stars on or near the main sequence, slightly more massive than the Sun. Subject headings: stars: oscillations — delta Scuti — survey — techniques: photometric