Abundance Analyses of RV Tauri Variables Virtual Observatory Resource

Authors
  1. Gonzalez G.
  2. Lambert D.L.
  3. Giridhar S.
  4. Published by
    CDS
Abstract

Analyses of the photospheric compositions of the four field RV Tauri stars, EP Lyr, DY Ori, AR Pup, and R Sge, indicate that to varying degrees they have experienced fractionation processes that have preferentially depleted their atmospheres of elements with high condensation temperatures. The depletion, as indicated by, for instance, [S/Fe], is greatest for DY Ori, [S/Fe]=2.5, and least for R Sge, [S/Fe]=0.9. The initial composition, presumably indicated by the sulfur abundance, was nearly solar for AR Pup, R Sge, and DY Ori, while it was about 0.6--- less than solar for EP Lyr. This implies that the RV Tauri stars as a group may not be as metal-poor as previously thought---they are instead ``metal-depleted''. The field RV Tauri's are not halo stars, but probably belong to the thick disk. This brings to seven the number of type II Cepheids that show such a trend; the other three are IW Car and V1 in omega Cen, RV Tauri stars, and ST Pup, a W Virginis star. The 12C/13C ratios for EP Lyr and DY Ori are 9+/-1 and 6+/-3, respectively, indicating that CN-cycled material has been mixed with their surface layers. This is consistent with the general consensus that RV Tau stars are in a post-AGB evolutionary stage. There is also evidence that EP Lyr has a stellar mass companion, but additional observations are required to calculate an orbit; hence, EP Lyr could be a link to the group of metal-depleted, high-latitude A-F supergiants, all of which are binaries.

Keywords
  1. variable-stars
  2. chemical-abundances
  3. horizontal-branch-stars
Bibliographic source Bibcode
1997ApJ...479..427G
See also HTML
https://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/479/427
IVOA Identifier IVOID
ivo://CDS.VizieR/J/ApJ/479/427
Document Object Identifer DOI
doi:10.26093/cds/vizier.14790427

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History

1997-12-09T21:01:11Z
Resource record created
1997-12-09T20:01:15Z
Updated
1997-12-09T21:01:11Z
Created

Contact

Name
CDS support team
Postal Address
CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France
E-Mail
cds-question@unistra.fr