The Horizontal Branch of NGC 1851: Constraints on the Cluster Subpopulations

Abstract

We investigate the distribution of stars along the Horizontal Branch of the Galactic globular cluster NGC1851, to shed light on the progeny of the two distinct Subgiant Branch populations harbored by this cluster. On the basis of detailed synthetic Horizontal Branch modelling, we conclude that the two subpopulations are distributed in different regions of the observed Horizontal Branch: the evolved stars belonging to the bright Subgiant branch component are confined in the red portion of the observed sequence, whereas the ones belonging to the faint Subgiant branch component are distributed from the blue to the red, populating also the RR Lyrae instability strip. Our simulations strongly suggest that it is not possible to reproduce the observations assuming that the two subpopulations lose the same amount of mass along the Red Giant Branch. We warmly encourage empirical estimates of mass loss rates in Red Giant stars belonging to this cluster.

12 pages, including 2 figures. Accepted for publication in ApJL

References in corpus (4)

• The ACS Survey of Galactic Globular Clusters. III. The Double Subgiant Branch of NGC 1851
• The double Subgiant Branch of NGC 1851: the role of the CNO abundance
• An abundance analysis of bright giants in the globular cluster NGC 1851
• The First Empirical Mass Loss Law for Population II Giants

Cited by in corpus (11)

• Multiple stellar populations in three rich Large Magellanic Cloud star clusters
• The fraction of second generation stars in Globular Clusters from the analysis of the Horizontal Branch
• A large C+N+O abundance spread in giant stars of the globular cluster NGC 1851
• Rapidly rotating second-generation progenitors for the blue hook stars of ω Cen
• Multiple stellar populations along the red Horizontal Branch and Red Clump of Globular Clusters
• The Na-O anticorrelation in horizontal branch stars. V. NGC 6723
• Evolutionary and pulsation properties of Type II Cepheids
• Multiple populations in massive star clusters under the magnifying glass of photometry: Theory and tools
• The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters -- XI. The horizontal branch in NGC\,6388 and NGC\,6441
• The Horizontal Branch population of NGC 1851 as revealed by the Ultra-violet Imaging Telescope (UVIT)
• A stellar population synthesis approach to the Oosterhoff dichotomy