Habitability in the Omega Centauri Cluster

Abstract

The search for exoplanets has encompassed a broad range of stellar environments, from single stars in the solar neighborhood to multiple stars and various open clusters. The stellar environment has a profound effect on planet formation and stability evolution and is thus a key component of exoplanetary studies. Dense stellar environments, such as those found in globular clusters, provide particularly strong constraints on sustainability of habitable planetary conditions. Here, we use Hubble Space Telescope observations of the core of the Omega Centauri cluster to derive fundamental parameters for the core stars. These parameters are used to calculate the extent of the habitable zone (HZ) of the observed stars. We describe the distribution of HZs in the cluster and compare them with the stellar density and expected stellar encounter rate and cluster dynamics. We thus determine the effect of the stellar environment within the Omega Centauri core on the habitability of planets that reside within the cluster. Our results show that the distribution of HZ outer boundaries generally lie within 0.5 au of the host stars, but that this small cross-sectional area is counter-balanced by a relatively high rate of stellar close encounters that would disrupt planetary orbits within the HZ of typical Omega Centauri stars.