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Title: The chemical compositions of RR Lyrae type c variable stars

We present a detailed chemical abundance study of eight RR Lyrae variable stars of subclass c (RRc). The target RRc stars chosen for study exhibit 'Blazhko-effect' period and amplitude modulations to their pulsational cycles. Data for this study were gathered with the echelle spectrograph of the 100 inch du Pont telescope at Las Campanas Observatory. Spectra were obtained throughout each star's pulsation cycle. Atmospheric parameters—effective temperature, surface gravity, microturbulent velocity, and metallicity—were derived at multiple phase points. We found metallicities and element abundance ratios to be constant within observational uncertainties over the pulsational cycles of all stars. Moreover, the α-element and Fe-group abundance ratios with respect to iron are consistent with other horizontal-branch members (RRab, blue and red non-variables). Finally, we have used the [Fe/H] values of these eight RRc stars to anchor the metallicity estimates of a large-sample RRc snapshot spectroscopic study being conducted with the same telescope and instrument combination employed here.
Authors:
; ;  [1] ;  [2]
  1. Department of Astronomy and McDonald Observatory, The University of Texas, Austin, TX 78712 (United States)
  2. The Observatories of the Carnegie Institution of Washington, Pasadena, CA 91101 (United States)
Publication Date:
OSTI Identifier:
22351444
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 782; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; AMPLITUDES; ANCHORS; ATMOSPHERES; CHEMICAL COMPOSITION; ELEMENT ABUNDANCE; GRAVITATION; IRON; METALLICITY; PULSATIONS; SPECTRA; SURFACES; TELESCOPES; VARIABLE STARS; VELOCITY