Titile: Binary origin of blue stragglers

Abstract:

In this talk, I will review binary evolution channels for blue stragglers (BSS) and their contribution to the 
integrated spectral-energy distribution (ISED) in simple stellar populations.

According to binary evolution, we can define three channels to BSS: (1) stable mass transfer; (2) 
coalescence of contact binaries, and (3) coalescence from dynamically unstable mass transfer. For a given 
binary population, one evolutionary channel may dominate the BSS formation at a certain age while another 
dominates at another age. Those scenarios and recent works on these will be addressed.

BSS can significantly change the ISED of their host cluster, especially at short wavelengths. Our binary 
population synthesis showed that BSS from channels (1) and (2) are dominant contributors to the ISEDs in 
ultraviolet and blue bands in a population between 0.3 and 2.0 Gyr, while those from channel (3) are 
dominant contributors in a population older than ~ 4Gyr. The inclusion of BSS in a simple stellar population 
makes the population look younger.