Identifying SRD Variables Among “Miscellaneous” ASAS Stars (Poster abstract)

Volume 44 number 1 (2016)

Michael Quinonez

Department of Physics and Earth Sciences, Central Connecticut State University, 1615 Stanley Street, New Britain, CT 06053; Larsen@ccsu.edu

Kristine Larsen

Department of Physics and Earth Sciences, Central Connecticut State University, 1615 Stanley Street, New Britain, CT 06053; Larsen@ccsu.edu

Abstract

(Abstract only) The International Variable Star Index (VSX) contains a large number of stars observed and analyzed by the All Sky Automated Survey (ASAS). While ASAS is a powerful tool in terms of the sheer volume of data it collects, its automated light curve analysis is not always robust enough to reliably identify stars that are not strictly regular in their magnitude variations. As a consequence, it was suspected that potentially many variable stars of the semiregular type were instead added to the VSX under a miscellaneous (MISC) classification. A subset of these semiregular stars, known as SRD variables, has a well-defined set of parameters regarding their classification—they are of the F, G, or K spectral type, their amplitudes of light variation are between 0.1 and 4 magnitudes, and their periods of variation can span 30 to 1,100 days. Furthermore, SRD variables are giants or supergiants, and therefore typically distant with small proper motions. A search was made through stars listed as MISC in the VSX using the above parameters, as well detailed light curve analyses via the AAVSO’s VStar program, in order to find ASAS SRDs that were misclassified as MISC. This study of 90 stars has yielded five new SRDs to date. In addition, some data pertaining to several stars that were not confirmed to be of the SRD type were found to contain errors, and have since been revised accordingly in VSX.