Cover Picture: Astron. Nachr. 6/2024

Abstract

Color-magnitude diagram of the lower mass end of the Main Sequence of globular cluster NGC 6752, as derived from NIR images of a deep field observed under a HST Large Programme led by L.R.Bedin. Three main stellar populations can be reliably distinguished within this cluster. The three isochrones (blue, green, and red lines) were computed with different chemical compositions, adjusted to match the observed colors of the different generations of stars at an age of 12.63 Gy. In the lower left part of the plot, the corresponding isochrone for the White Dwarfs (at an age of 12.5 Gy) is shown in purple, together with the three WD candidates shown as orange crosses. For each isochrone, specific mass values are marked by labeled filled dots. A detailed analysis of the HST data and a discussion of possible scenarios for the formation of multiple stellar populations within NGC 6752 is presented in the article by Scalco et al., this issue e240018.