A systematic study of effects of stellar rotation, age spread and binaries on color-magnitude diagrams with extended main-sequence turn-offs

Abstract

Stellar rotation, age spread and binary stars are thought to be three most possible causes of the peculiar color-magnitude diagrams (CMDs) of some star clusters, which exhibit extended main-sequence turn-offs (eMSTOs). It is far from getting a clear answer. This paper studies the effects of three above causes on the CMDs of star clusters systematically. A rapid stellar evolutionary code and a recently published database of rotational effects of single stars have been used, via an advanced stellar population synthesis technique. As a result, we find a consistent result for rotation to recent works, which suggests that rotation is able to explain, at least partially, the eMSTOs of clusters, if clusters are not too old ($<$ 2.0\,Gyr). In addition, an age spread of 200 to 500\,Myr reproduces extended turn-offs for all clusters younger than 2.5\,Gyr, in particular, for those younger than 2.2\,Gyr. Age spread also results in extended red clumps (eRCs) for clusters younger than 0.5\,Gyr. The younger the clusters, the clearer the eRC structures. Moreover, it is shown that binaries (including interactive binaries) affect the spread of MSTO slightly for old clusters, but they can contribute to the eMSTOs of clusters younger than 0.5\,Gyr. Our result suggests a possible way to disentangle the roles of stellar rotation and age spread, i.e., checking the existence of CMDs with both eMSTO and eRC in clusters younger than 0.5\,Gyr.

Accepted to publish in ApJS

References in corpus (17)

• Formation and Dynamical Evolution of Multiple Stellar Generations in Globular Clusters
• Age Determination of Six Intermediate-age SMC Star Clusters with HST/ACS
• A double main sequence turn-off in the rich star cluster NGC 1846 in the Large Magellanic Cloud
• Multiple stellar populations in three rich Large Magellanic Cloud star clusters
• Multiple stellar populations in Magellanic Clouds clusters. I. An ordinary feature for intermediate age globulars in the LMC?
• The chemical composition of red giant stars in four intermediate-age clusters of the Large Magellanic Cloud
• Extended Main Sequence Turnoffs in Intermediate-Age Star Clusters: A Correlation Between Turnoff Width and Early Escape Velocity
• Discovery of two distinct red clumps in NGC419: a rare snapshot of a cluster at the onset of degeneracy
• Rotating Stellar Models Can Account for the Extended Main Sequence Turnoffs in Intermediate Age Clusters
• The exclusion of a significant range of ages in a massive star cluster
• Evolutionary Population Synthesis for Binary Stellar Populations
• New Clues to the Cause of Extended Main Sequence Turn-Offs in Intermediate-Age Star Clusters in the Magellanic Clouds
• Controversial Age Spreads from the Main Sequence Turn-Off and Red Clump in Intermediate-Age Clusters in the LMC
• An Isochrone Database and a Rapid Model for Stellar Population Synthesis
• How binary interactions affect spectral stellar population synthesis
• Explanation of a special color-magnitude diagram of star cluster NGC 1651 from different models
• Binary interactions as a possible scenario for the formation of multiple stellar populations in globular clusters

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