Affiliation:
1. The W.J. McDonald Observatory & The Department of Astronomy, The University of Texas at Austin , Austin, TX 78712 , USA
Abstract
ABSTRACT
A sample of warm, low-level semiregular variables chosen from the General Catalogue of Variable Stars is studied for their chemical compositions by analysing high-resolution optical spectra. The abundance ratios from Na/Fe to Eu/Fe displayed by these and previously analysed semiregular variables are quite similar to ratios displayed by normal red giants across the Galactic thin and thick discs and halo populations in the solar neighbourhood, suggesting from this perspective that the variables may be among the more photometrically active red giants.
Funder
European Space Agency
National Development and Reform Commission
Chinese Academy of Sciences
Alfred P. Sloan Foundation
U.S. Department of Energy Office of Science
Publisher
Oxford University Press (OUP)