Asteroseismology of the multiple stellar populations in the globular cluster M4

Vol. 662
1. Letters to the Editor

Asteroseismology of the multiple stellar populations in the globular cluster M4

The detection of solar-like oscillations in stellar clusters has an enormous potential, although it is a challenging task, particularly for globular clusters that are far away and affected by crowding. Among the old Galactic globular clusters, only M4 is currently accessible to this kind of research. The authors have taken advantage of observations with the NASA Kepler satellite to detect oscillations with a power excess in 37 cluster members, the largest sample of solar-like oscillators in a globular cluster to date, which includes both red giant branch and red horizontal branch stars.

For the first time, an asteroseismic characterization of the multiple stellar populations hosted in this cluster has been possible; the masses and radii estimated for these stars are in very good agreement with the values obtained with more classical methods, and the authors confirm that the difference in mass among stars belonging to the cluster multiple populations is quite small. Moreover, the characterization of a good number of red horizontal branch stars has provided solid confirmation that these objects lose a fairly high amount of mass, and that stellar mass loss in globular clusters seems to be a different phenomenon compared to that in younger stellar associations.