In search of RR Lyrae type stars in eclipsing binary systems (Research Note) : OGLE052218.07-692827.4: an optical blend

• Published in: Astronomy and astrophysics (Berlin) Vol. 489; no. 3; pp. 1209 - 1212
• Main Authors: PRSA, A, GUINAN, E. F, DEVINNEY, E. J, ENGLE, S. G
• Format: Journal Article
• Language: English
• Published: Les Ulis EDP Sciences 01.10.2008
• Subjects: Astronomy; Earth, ocean, space; Exact sciences and technology; Eclipsing binary stars; stars: individual: OGLE052218.07-692827.4; Data analysis; methods: observational; RR Lyrae stars; methods: data analysis; stars: binaries: close; Close binary stars; stars: variables: RR Lyr; Models; stars: binaries: eclipsing; Large Magellanic Cloud
• ISSN: 0004-6361; 1432-0746
• DOI: 10.1051/0004-6361:200810486

During the OGLE-2 operation, Soszynski et al. (2003) found 3 LMC candidates for an RR Lyr-type component in an eclipsing binary system. Two of those have orbital periods that are too short to be physically plausible and hence have to be optical blends. For the third, OGLE052218.07-692827.4, we developed a model of the binary that could host the observed RR Lyr star. After being granted HST/WFPC2 time, however, we were able to resolve 5 distinct sources within a 1.3'' region that is typical of OGLE resolution, proving that OGLE052218.07-692827.4 is also an optical blend. Moreover, the putative eclipsing binary signature found in the OGLE data does not seem to correspond to a physically plausible system; the source is likely another background RR Lyr star. There are still no RR Lyr stars discovered so far in an eclipsing binary system.