The discovery of multiple stellar populations in Milky Way globular clusters (GCs) has stimulated various follow-up studies on helium-enhanced stellar populations. Here we present the evolutionary population synthesis models for the spectro-photometric evolution of simple stellar populations (SSPs) with varying initial helium abundance (Y ini). We show that Y ini brings about dramatic changes in spectro-photometric properties of SSPs. Like the normal-helium SSPs, the integrated spectro-photometric evolution of helium-enhanced SSPs is also dependent on metallicity and age for a given Y ini. We discuss the implications and prospects for the helium-enhanced populations in relation to the second-generation populations found in the Milky Way GCs. All of the models are available at http://web.yonsei.ac.kr/cosmic/data/YEPS.htm.
Bibliographical noteFunding Information:
We thank the referee for helpful suggestions. Y.W.L. and S.J.Y. acknowledge support from the National Research Foundation of Korea to the Center for Galaxy Evolution Research. S.J.Y. acknowledges support from Mid-career Researcher Program (No. 2012R1A2A2A01043870) through the National Research Foundation (NRF) of Korea grant funded by the Ministry of Science, ICT, and Future Planning (MSIP). This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government(MSIP) (No. 2017R1A2B3002919).
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science