Mon. Not. R. Astron. Soc., 459, 4360-4377 (2016/July-2)
Cyclic variations in O-C diagrams of field RR Lyrae stars as a result of LiTE.
LISKA J., SKARKA M., ZEJDA M., MIKULASEK Z. and DE VILLIERS S.N.
Abstract (from CDS):
This paper presents an extensive overview of known and proposed RR Lyrae stars in binaries. The aim is to revise and extend the list with new Galactic field systems. We utilized maxima timings for 11 RRab type stars with suspicious behaviour from the GEOS data base, and determined maxima timings from data of sky surveys and our own observations. This significantly extended the number of suitable maxima timings. We modelled the proposed Light Time Effect (LiTE) in O-C diagrams to determine orbital parameters for these systems. In contrast to recent studies, our analysis focused on decades-long periods instead of periods in the order of years. Secondary components were found to be predominantly low-mass objects. However, for RZ Cet and AT Ser the mass of the suspected companion of more than one solar mass suggests that it is a massive white dwarf, a neutron star or even a black hole. We found that the semimajor axes of the proposed orbits are between 1 and 20 au. Because the studied stars belong to the closest RR Lyraes, maximal angular distances between components during orbit should at least be between 1 and 13 mas and this improves the chance to detect both stars using current telescopes. However, our interpretation of the O-C diagrams as a consequence of the LiTE should be considered as preliminary without reliable spectroscopic measurements. On the other hand, our models give a prediction of the period and radial velocity evolution which should be sufficient for plausible proof of binarity.
© 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society
methods: data analysis - techniques: photometric - binaries: general - stars: horizontal branch - stars: variables: RR Lyrae - stars: variables: RR Lyrae
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<Available at CDS (J/MNRAS/459/4360): table1.dat table2.dat table3.dat table4.dat table5.dat table6.dat refs.dat>
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