The stellar population of Her consists mainly of old stars formed more than 12 billion years ago.
One possible explanation for this would be the presence of more than one stellar population.
Both events were, however, associated with actively star-forming stellar populations.
The situation is further complicated by the fact that different stellar populations generally do not have all types of stars in them.
Based upon the abundance measurements, there is evidence that this cluster hosts two distinct stellar populations.
He was known for his wide range of research interests, from stellar populations to cosmology.
Unlike M36 or M37, M38 has a varied stellar population.
It will yield important information on the ages of the stellar populations.
The stellar population of this cluster is inhomogeneous, varying with distance from the core.
The colors in this image reflect the intrinsic color of the different stellar populations that make up the galaxies.
