PAGB stars in binary stellar population synthesis model
Abstract
Post Asymptotic Giant Branch (PAGB) stars are luminous objects (103 - 104L⊙) in final stages of their evolution before reaching the white dwarf cooling sequence. They are an important key to understand galaxy evolution since they are hot enough to contribute to the UV excess in old stellar systems. Binary interactions may change the evolutionary path over the HR diagram and the total number of PAGB stars may also change. In this contribution we remark that rare Yellow PAGB stars are formed through mass transfer in a binary system, however the probability of formation is low. We use a recent implementation of the BC03 stellar population synthesis model that allows a stochastic sampling of the initial mass function to evolve single stars. We select, assemble and evolve binary systems using our binary code. We run ten realizations of simulated clusters for a Z=0.0005, M=106M_⊙, BF=0.9. One evolved stars formed in a binary system appears near the region of observed yellow PAGB stars. To demonstrate that these rare stars may be form through binary interaction, we select binary pairs with period less than critical to ensure mass transfer. The yellow PAGB star is formed by binary interaction. Binary and stochastic effects on the formation of yellow PAGB and the influence on spectral and photometric properties of the stellar systems will be studied in future work.
- Publication:
-
Revista Mexicana de Astronomia y Astrofisica Conference Series
- Pub Date:
- July 2017
- Bibcode:
- 2017RMxAC..49R.163H