Ultra-low Amplitude Variables in the LMC - Classical Cepheids, Pop. II Cepheids, RV Tau Stars and Binary Variables - Astrophysics > Solar and Stellar AstrophysicsReportar como inadecuado




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Abstract: A search for variable stars with ultra-low amplitudes ULA, in the millimagrange, has been made in the combined MACHO and OGLE data bases in the broadvicinity of the Cepheid instability strip in the HR diagram. A total of 25singly periodic and 4 multiply periodic ULA objects has been uncovered. Ouranalysis does not allow us to distinguish between pulsational and ellipsoidalbinary variability, nor between LMC and foreground objects. However, theobjects are strongly clustered and appear to be associated with the pulsationalinstability strips of LMC Pop. I and II variables. When combined with the ULAvariables of Buchler et al 2005 a total of 20 objects fall close to theclassical Cepheid instability strip. However, they appear to fall on parallelperiod-magnitude relations that are shifted to slightly higher magnitude whichwould confer them a different evolutionary status. Low amplitude RV Tauri andPop. II Cepheids have been uncovered that do not appear in the MACHO or OGLEcatalogs. Interestingly, a set of binaries seem to lie on a PM relation that isessentially parallel to that of the RV Tauri-Pop. II Cepheids.



Autor: J. Robert Buchler, Peter R. Wood, Igor Soszynski

Fuente: https://arxiv.org/







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