A helium spread among the main sequence stars in NGC 2808

Abstract

We studied the color distribution of the main sequence of the Globular Cluster NGC 2808, based on new deep HST-WFPC2 photometry of a field in the uncrowded outskirts of the cluster. The color distribution of main sequence stars is wider than expected for a single stellar population, given our (carefully determined) measurement errors. About 20% of the sample stars are much bluer than expected and are most plausibly explained as a population having a much larger helium abundance than the bulk of the main sequence. We estimate that the helium mass fraction of these stars is Y ~ 0.4. NGC 2808 may have suffered self-enrichment, with different stellar populations born from the ejecta of the intermediate mass asymptotic giant branch (AGB) stars of the first generation. In addition to the Y=0.40 stars, roughly 30% of the stars should have Y distributed between 0.26-0.29 while 50% have primordial Y, to explain also the peculiar horizontal branch morphology. Three main stages of star formation are identified, the first with primordial helium content Y ~ 0.24, the second one born from the winds of the most massive AGBs of the first stellar generation (6-7msun), having Y ~ 0.4, and a third one born from the matter ejected from less massive AGBs (~ 3.5-4.5msun) with Y ~ 0.26-0.29. For a long hiatus of time (several 10^7yr) between the second and third generation, star formation might have been inhibited by the explosion of late Supernovae II deriving from binary evolution.

accepted for publication on "The Astrophysical Journal"

References in corpus (27)

• WFPC2 Stellar Photometry with HSTphot
• Omega Centauri: The Population Puzzle Goes Deeper
• The O-Na and Mg-Al Anticorrelations in Turn-Off and early Subgiants in Globular Clusters
• Predictions for self-pollution in globular cluster stars
• Multiple Stellar Populations in the Globular Cluster omega Centauri as Tracers of a Merger Event
• A dwarf galaxy remnant in Canis Major: the fossil of an in-plane accretion onto the Milky Way
• The giant, horizontal and asymptotic branches of galactic globular clusters. I. The catalog, photometric observables and features
• Helium variation due to self-pollution among Globular Cluster stars: consequences on the horizontal branch morphology
• The Origin of Extreme Horizontal Branch Stars
• The early evolution of Globular Clusters: the case of NGC 2808
• Discovery of Extended Blue Horizontal Branches in Two Metal-Rich Globular Clusters
• New evidence for the complex struscture of the RGB of Omega Cen
• Super Helium-Rich Population and the Origin of Extreme Horizontal-Branch Stars in Globular Clusters
• Flash Mixing on the White Dwarf Cooling Curve: Understanding Hot Horizontal Branch Anomalies in NGC 2808
• Full computation of massive AGB evolution. I. The large impact of convection on nucleosynthesis
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• Deep HST-WFPC2 photometry of NGC 288. I. Binary Systems and Blue Stragglers
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• Discovery of an anomalous Sub Giant Branch in the Color Magnitude Diagram of omega Centauri
• Spectroscopic Analyses of the Blue Hook Stars in NGC 2808: A More Stringent Test of the Late Hot Flasher Scenario
• HST Observations of New Horizontal Branch Structures in the Globular Cluster omega Centauri
• Detection of the Canis Major galaxy at (l;b)=(244;-8) and in the background of Galactic open clusters
• Globular Cluster and Galaxy Formation: M31, the Milky Way and Implications for Globular Cluster Systems of Spiral Galaxies
• Helium self--enrichment and the second parameter problem in M3 and M13
• Star-to-star Na and O abundance variations along the red giant branch in NGC 2808
• Proton capture elements in the globular cluster NGC 2808 I. First detection of large variations in Sodium abundances along the Red Giant Branch
• Discovery of a Variable Star Population in NGC 2808

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