Metal-rich SX Phe stars in the Kepler field
Article
Article Title | Metal-rich SX Phe stars in the Kepler field |
---|---|
ERA Journal ID | 1074 |
Article Category | Article |
Authors | Nemec, James M. (Author), Balona, Luis A. (Author), Murphy, Simon J. (Author), Kinemuchi, Karen (Author) and Jeon, Young-Beom (Author) |
Journal Title | Monthly Notices of the Royal Astronomical Society |
Journal Citation | 466 (2), pp. 1290-1329 |
Number of Pages | 40 |
Year | 2016 |
Publisher | Oxford University Press |
Place of Publication | United Kingdom |
ISSN | 0035-8711 |
1365-2966 | |
Digital Object Identifier (DOI) | https://doi.org/10.1093/mnras/stw3072 |
Web Address (URL) | https://academic.oup.com/mnras/article/466/2/1290/2608773 |
Abstract | A spectroscopic and photometric analysis has been carried out for 32 candidate SX Phe variable blue straggler stars in the Kepler field. Radial velocities (RVs), space motions (U, V, W), projected rotation velocities (vsin i), spectral types and atmospheric characteristics (Teff, log g, [Fe/H], ξt, ζRT, etc.) are presented for 30 of the 32 stars. Although several stars are metal-weak with extreme halo orbits, the mean [Fe/H] of the sample is near-solar, thus the stars are more metal-rich than expected for a typical sample of Pop. II stars and more like halo metal-rich A-type stars. Two-thirds of the stars are fast rotators with vsin i > 50 km s−1, including four stars with vsin i > 200 km s−1. Three of the stars have (negative) RVs > 250 km s−1, five have retrograde space motions and 21 have total speeds (relative to the Local Standard of Rest) >400 km s−1. All but one of the 30 stars have positions in a Toomre diagram consistent with the kinematics of bona fide halo stars (the exception being a thick-disc star). Observed Rømer time delays, pulsation frequency modulations and light curves suggest that at least one-third of the stars are in binary (or triple) systems with orbital periods ranging from 2.3 d to more than four years. |
Keywords | Blue stragglers; Stars: abundances; Stars: kinematics and dynamics; Stars: oscillations; Stars: Population II; Stars: variables: δ Scuti; Astrophysics - Solar and Stellar Astrophysics |
ANZSRC Field of Research 2020 | 510109. Stellar astronomy and planetary systems |
Public Notes | This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2016 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. |
Byline Affiliations | Camosun College, Canada |
South African Astronomical Observatory, South Africa | |
University of Sydney | |
Apache Point Observatory, United States | |
Korea Astronomy and Space Science Institute, Korea | |
Institution of Origin | University of Southern Queensland |
https://research.usq.edu.au/item/q73v5/metal-rich-sx-phe-stars-in-the-kepler-field
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