Multiple main sequence of globular clusters as a result of inhomogeneous big bang nucleosynthesis

Journal Article · Mon Feb 15 00:00:00 EST 2010 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.81.043004· OSTI ID:21409251

Moriya, Takashi; Shigeyama, Toshikazu ^[1]

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1. Department of Astronomy, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan, and Institute for the Physics and Mathematics of the Universe, University of Tokyo, Kashiwanoha 5-1-5, Kashiwa, Chiba 277-8583 (Japan)

A new mechanism for enhancing the helium abundance in the blue main sequence stars of {omega} Centauri and NGC 2808 is investigated. We suggest that helium enhancement was caused by the inhomogeneous big bang nucleosynthesis. Regions with extremely high baryon-to-photon ratios are assumed to be caused by the baryogenesis. Its mass scale is also assumed to be 10{sup 6}M{sub {center_dot}.} An example of the mechanisms to realize these two things was already proposed as the Affleck-Dine baryogenesis. As the baryon-to-photon ratio becomes larger, the primordial helium abundance is enhanced. We calculated the big bang nucleosynthesis and found that there exists a parameter region yielding enough helium to account for the split of the main sequence in the aforementioned globular clusters while keeping the abundance of other elements compatible with observations. Our mechanism predicts that heavy elements with the mass number of around 100 is enhanced in the blue main sequence stars. We estimate the time scales of diffusion of the enhanced helium and mass accretion in several stages after the nucleosynthesis to investigate whether these processes diminish the enhancement of helium. We found that the diffusion does not influence the helium content. A cloud with a sufficiently large baryon-to-photon ratio to account for the multiple main sequence collapsed immediately after the recombination. Subsequently, the cloud accreted the ambient matter with the normal helium content. If the star formation occurred both in the collapsed core and the accreted envelope, then the resultant star cluster has a double main sequence.

• OSTI ID: 21409251
• Journal Information: Physical Review. D, Particles Fields, Vol. 81, Issue 4; Other Information: DOI: 10.1103/PhysRevD.81.043004; (c) 2010 The American Physical Society; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ABUNDANCE
COMPUTERIZED SIMULATION
DIFFUSION
HELIUM
MAIN SEQUENCE STARS
MASS
MASS NUMBER
NUCLEOSYNTHESIS
PHOTONS
RECOMBINATION
STAR CLUSTERS
BOSONS
ELEMENTARY PARTICLES
ELEMENTS
FLUIDS
GASES
MASSLESS PARTICLES
NONMETALS
RARE GASES
SIMULATION
STARS
SYNTHESIS