Advances in Astronomy and Space Physics, Volume 5, Issue 1, PP. 24-28 (2015)
doi: 10.17721/2227-1481.5.24-28

Contamination of RR Lyrae stars from
Binary Evolution Pulsators

P. Karczmarek

Warsaw University Observatory, Al. Ujazdowskie 4, 00-478, Warsaw, Poland

Abstract
A Binary Evolution Pulsator (BEP) is a low-mass (0.26 𝔐☉) member of a binary system, which pulsates as a result of a former mass transfer to its companion. The BEP mimics RR Lyrae-type pulsations, but has completely different internal structure and evolution history. Although there is only one known BEP (OGLE-BLG-RRLYR-02792), it has been estimated that approximately 0.2% of objects classified as RR Lyrae stars can be undetected Binary Evolution Pulsators. In the present work, this contamination value is re-evaluated using the population synthesis method. The output falls inside a range of values dependent on tuning the parameters in the StarTrack code, and varies from 0.06% to 0.43%.

Keywords:
methods: numerical - variables: RR Lyrae - binaries

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