Variable stars in Local Group Galaxies: I. tracing the early chemical enrichment and radial gradients in the Sculptor dSph with RR Lyrae stars

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DOIResolve DOI: http://doi.org/10.1093/mnras/stv2014
AuthorSearch for: ; Search for: ; Search for: ; Search for: ; Search for: ; Search for: ; Search for: ; Search for: ; Search for: ; Search for:
TypeArticle
Journal titleMonthly Notices of the Royal Astronomical Society
ISSN0035-8711
1365-2966
Volume454
Issue2
Pages15091516
SubjectKstars: variables: RR Lyrae; galaxies: evolution; galaxies: individual: Sculptor dSph; Local Group; galaxies: stellar content
AbstractWe identified and characterized the largest (536) RR Lyrae (RRL) sample in a Milky Way dSph satellite (Sculptor) based on optical photometry data collected over ∼24 years. The RRLs display a spread in V-magnitude (∼0.35 mag) which appears larger than photometric errors and the horizontal branch (HB) luminosity evolution of a mono-metallic population. Using several calibrations of two different reddening free and metal independent period–Wesenheit relations we provide a new distance estimate μ = 19.62 mag (σμ = 0.04 mag) that agrees well with literature estimates. We constrained the metallicity distribution of the old population, using the MI period–luminosity relation, and we found that it ranges from −2.3 to −1.5 dex. The current estimate is narrower than suggested by low and intermediate spectroscopy of RGBs (Δ [Fe/H]≤ 1.5). We also investigated the HB morphology as a function of the galactocentric distance. The HB in the innermost regions is dominated by red HB stars and by RRLs, consistent with a more metal-rich population, while in the outermost regions it is dominated by blue HB stars and RRLs typical of a metal-poor population. Our results suggest that fast chemical evolution occurred in Sculptor, and that the radial gradients were in place at an early epoch.
Publication date
PublisherOxford University Press
LanguageEnglish
AffiliationNRC Herzberg Astronomy and Astrophysics; National Research Council Canada
Peer reviewedYes
NPARC number23001711
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Record identifier918adfc7-d2b4-4cff-805f-986ed484d990
Record created2017-03-21
Record modified2017-03-30
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