A binary study of color-magnitude diagrams of 12 globular clusters

Binary stars are common in star clusters and galaxies, but the detailed ef- fects of binary evolution are not taken into account in some color-magnitude diagram （CMD） studies. This paper studies the CMDs of twelve globular clusters via binary- star stellar populations. The observational CMDs of the star clusters are compared to those of binary-star populations, and then the stellar metallicities, ages, distances and reddenings of these star clusters are obtained. The paper also tests the different effects of binary and single stars on CMD studies. It is shown that binaries can better fit the observational CMDs of the sample globular clusters compared to single stars. This suggests that the effects of binary evolution should be considered when modeling the CMDs and stellar populations of star clusters and galaxies.

Powerful CMD:a tool for color-magnitude diagram studies

We present a new tool for color-magnitude diagram（CMD） studies, Powerful CMD. This tool is built based on the advanced stellar population synthesis（ASPS） model, in which single stars, binary stars, rotating stars and star formation history have been taken into account. Via Powerful CMD, the distance modulus, color excess, metallicity, age, binary fraction, rotating star fraction and star formation history of star clusters can be determined simultaneously from observed CMDs. The new tool is tested via both simulated and real star clusters. Five parameters of clusters NGC 6362, NGC 6652, NGC 6838 and M67 are determined and compared to other works. It is shown that this tool is useful for CMD studies, in particular for those utilizing data from the Hubble Space Telescope（HST）. Moreover, we find that inclusion of binaries in theoretical stellar population models may lead to smaller color excess compared to the case of single-star population models.

A database of spectral energy distributions of progenitors of core-collapse supernovae

This paper presents a database of the spectroscopic-and photometric-spectral energy distributions(spec-SEDs and phot-SEDs respectively)of the progenitors of core-collapse supernovae(CCSNe).Both binary-and single-star progenitors are included in the database.The database covers the initial metallicity(Z)range of 0.0001-0.03,mass range of 8-25 M⊙,binary mass ratio range of 0-1,and orbital period range of 0.1-10000 d.The low-resolution spec-SEDs and phot-SEDs of single-and binary-star CCSN progenitors are included in the database.These data can be used for studying the basic parameters,e.g.,metallicity,age,and initial and final masses of CCSN progenitors.It can also be used for studying the effects of different factors on the determination of parameters of CCSN progenitors.When the database is utilized for fitting the SEDs of binary-star CCSN progenitors,it is strongly suggested to determine the metallicity and orbital period in advance,but this is not necessary for single-star progenitors.