ASAS Candidates for Misidentified SRd Variable Stars

The All Sky Automated Survey (ASAS) is an observation project dedicated to the constant collection of photometric data across the entire sky. By default, ASAS classifies variable stars exhibiting any irregularity in their periodicity as miscellaneous. Unfortunately, there are many types of definitive variables that exhibit irregularities and are thus misidentified. A sample of approximately 1500 stars deemed miscellaneous by ASAS was initially obtained and candidates for a particular type of semi-regular variable were sought. These are SRd variables, giant and supergiant stars that pulsate as a result of an inability to assume hydrostatic equilibrium. Specifically, these variables belong to spectral classes F, G, K and have periods between 30 and 1100 days. Various parameters were used to clear the initial sample of definitive non-SRd candidates, including magnitude range, proper motion and photometric J-K value. VSTAR, an analysis software provided by the AAVSO, was then used to decompose the light curves of the remaining stars into their respective periods. Light curve and period phase plot behavior were used as a qualitative method for SRd candidate identification. From a subsample of 30 stars fitting the required parameters, 9 were found to exhibit light curve and phase plot characteristics that suggest SRd candidacy; the 6 with the most definitive behavior will be presented. A potential candidate for an eclipsing binary system was also discovered in the search for SRds.