Gomel, R, Shahaf, S, Mazeh, T, Faigler, S, Crause, LA, Sefako, R, Segransan, D, Maxted, PFL and Soszyński, I (2019) SB 796: a high-velocity RRc star. Monthly Notices of the Royal Astronomical Society, 482 (4). pp. 5327-5335. ISSN 0035-8711

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We report here on a detailed study of a c-type RR Lyrae variable (RRc variable), SB 796, serendipitously discovered in a search of the WASP public data for stars that display large photometric periodic modulation. SB 796 displays a period of P = 0.26585 d and semi-amplitude of ∼ 0.1 mag. Comparison of the modulation shape and period with the detailed analysis of LMC variables indicates that SB 796 is an RRc variable. Gaia DR2 classification corroborated our result. Radial-velocity (RV) follow-up observations revealed a periodic variation consistent with a sine modulation, with a semi-amplitude of 5.6 ± 0.2 km/s, and a minimum at phase of maximum brightness. Similar amplitude and phase were previously seen in other RRc variables. The stellar averaged RV is ∼250 km/s, turning SB 796 to be a high-velocity star, while its present position, as derived from the Gaia astrometry, is at ∼3.5 kpc below the Galactic plane. Integration of the stellar Galactic motion shows that SB 796 oscillates at a range of 0.5–20 kpc Galacto-centric distance, passing near the Galactic center about three times in 1 Gyr. The Galactic radial motion takes SB 796 up and down the plane to a scale height of ∼10 kpc. During its ∼10 Gyrs estimated life time, SB 796 therefore passed ∼30 times near the Galactic center.

Item Type: Article
Additional Information: This is the accepted author manuscript (AAM). The final published version (version of record) is available online via OUP at https://doi.org/10.1093/mnras/sty2828 - Please refer to any applicable terms of use of the publisher.
Uncontrolled Keywords: stars: variables: RR Lyrae – stars: Population II – Galaxy: kinematics and dynamics – Galaxy: halo
Subjects: Q Science > QB Astronomy
Q Science > QB Astronomy > QB460 Astrophysics
Divisions: Faculty of Natural Sciences > School of Chemical and Physical Sciences
Depositing User: Symplectic
Date Deposited: 14 Nov 2018 10:44
Last Modified: 29 Mar 2021 09:30
URI: https://eprints.keele.ac.uk/id/eprint/5504

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