Barium and Tc-poor S stars: Binary masqueraders among carbon stars
Abstract
Description
The current understanding of the origin of barium and S stars is reviewed, based on new orbital elements and binary frequencies. The following questions are addressed: (i) Is binarity a necessary condition to produce a barium star? (ii) What is the mass transfer mode (wind accretion or RLOF?) responsible for their formation? (iii) Do barium stars form as dwarfs or as giants? (iv) Do barium stars evolve into Tc-poor S stars? (v) What is the relative frequency of Tc-rich and Tc-poor S stars?
11 pages, 6 figures, Latex, to appear in IAU Symp. 177, The Carbon Star Phenomenon. Also available at http://astro.ulb.ac.be/Htm/ps.htm
11 pages, 6 figures, Latex, to appear in IAU Symp. 177, The Carbon Star Phenomenon. Also available at http://astro.ulb.ac.be/Htm/ps.htm