Multivariate Analysis of Globular Cluster's Horizontal Branch Morphology: searching for the second parameter

Abstract

The interpretation of globular cluster horizontal branch (HB) morphology is a classical problem that can significantly blur our understanding of stellar populations. In this paper, we present a new multivariate analysis connecting the effective temperature extent of the HB with other cluster parameters. The work is based on Hubble Space Telescope photometry of 54 Galactic globular clusters. The present study reveals an important role of the total mass of the globular cluster on its HB morphology. More massive clusters tend to have HBs more extended to higher temperatures. For a set of three input variables including the temperature extension of the HB, [Fe/H] and M_V, the first two eigenvectors account for the 90% of the total sample variance. Possible effects of cluster self-pollution on HB morphology, eventually stronger in more massive clusters, could explain the results here derived.

arXiv commentAccepted for publication in Astronomy & Astrophysics

References in corpus (20)

• Abundances for Globular Cluster Giants: I. Homogeneous Metallicities for 24 Clusters
• The O-Na and Mg-Al Anticorrelations in Turn-Off and early Subgiants in Globular Clusters
• Helium variation due to self-pollution among Globular Cluster stars: consequences on the horizontal branch morphology
• HST color-magnitude diagrams of 74 galactic globular clusters in the HST F439W and F555W bands
• Galactic Globular Cluster Relative Ages. II
• Galactic Globular Cluster Relative Ages
• Relative Frequencies of Blue Stragglers in Galactic Globular Clusters: Constraints for the Formation Mechanisms
• The Initial Helium Abundance of the Galactic Globular Cluster System
• Comparison between predicted and empirical DV(Bump -HB) in Galactic Globular Clusters
• Galactic Globular Cluster Stars: from Theory to Observation
• HST Observations of Galactic Globular Cluster Cores. II. NGC 6273 and the Problem of Horizontal-Branch Gaps
• Horizontal branch morphology in galactic globular clusters: dense environment is "a" second parameter
• On the helium content of Galactic globular clusters via the R parameter
• The Red Giant Branch Luminosity Function Bump
• Rotation, Planets, and the "Second Parameter" of the Horizontal Branch
• A Homogenous Set of Globular Cluster Relative Distances and Reddenings
• Age as the Second Parameter in NGC 288/NGC 362? II. The Horizontal Branch Revisited
• On the observational properties of He-burning stars: some clues on the tilt of the HB in metal rich clusters
• Asymptotic Giant Branch predictions: theoretical uncertainties
• Discovery of Blue Hook Stars in the Massive Globular Cluster M54

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