Results 11 to 20 of about 1,072 (156)
Helium-rich EHB Stars in Globular Clusters [PDF]
Astrophysics and Space Science, 2004 Recent UV observations of the most massive Galactic globular clusters show a significant population of hot stars below the zero-age HB (``blue hook'' stars), which cannot be explained by canonical stellar evolution. Stars which suffer unusually large mass loss on the red giant branch and thus experience the helium-core flash while descending the white ...
Moehler, S. +3 more
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On the formation of single and binary helium-rich sdO stars [PDF]
Monthly Notices of the Royal Astronomical Society, 2010 We propose a formation channel for the previously unexplained helium-rich subdwarf O (He-rich sdO) stars in which post-subdwarf B (sdB) stars (i.e. hybrid COHe white dwarfs) reignite helium burning in a shell after gaining matter from their helium white-dwarf (WD) companions.
Justham, S, Podsiadlowski, P, Han, Z
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On the Origin of Helium Rich Stars [PDF]
International Astronomical Union Colloquium, 1985 Abstract:The modem theory of stellar evolution leads to several possible scenaria for the formation of many types of hydrogen deficient (usually helium rich) stars. Some of these scenaria are briefly discussed in this paper to provide possible explanations for origins of R Cr B, hot helium and Wolf-Rayet stars; hot sub dwarfs, non-DA degenerate dwarfs ...
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SUPERBURST MODELS FOR NEUTRON STARS WITH HYDROGEN- AND HELIUM-RICH ATMOSPHERES [PDF]
The Astrophysical Journal, 2012 Superbursts are rare day-long Type I X-ray bursts due to carbon flashes on accreting neutron stars in low-mass X-ray binaries. They heat the neutron star envelope such that the burning of accreted hydrogen and helium becomes stable, and the common shorter X-ray bursts are quenched. Short bursts reappear only after the envelope cools down.
Keek, L. +2 more
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Helium Rich Subdwarf O Stars and Central Stars of Planetary Nebulae [PDF]
International Astronomical Union Colloquium, 1985 In this review we will discuss the hottest subluminous H-deficient stars, namely those with Teff> 30000 K. In the absence of reliable distance determinations for hot subluminous stars, the best way to discuss their properties and evolutionary status is to find their positions on the log g - log Teffdiagram.
R.H. Méndez +3 more
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First stars as a possible origin for the helium-rich population in ω Cen [PDF]
Monthly Notices of the Royal Astronomical Society: Letters, 2006 Abstract The most massive Galactic globular cluster ω Cen appears to have two, or perhaps more, distinct main sequences. Its bluest main sequence is at the centre of debate because it has been suggested to have an extremely high helium abundance of Y ∼ 0.4.
Ena Choi, Sukyoung K. Yi
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Recent Results Pertaining to the Helium-Rich Stars [PDF]
Symposium - International Astronomical Union, 1976 The term helium-rich stars here refers to those stars with apparent spectral types near B2 ana helium lines which are enhanced, but not stronger than the hydrogen lines. The previously known helium-rich star HD 184927 has been found to be a spectrum variable; the equivalent widths of the helium lines changed by an average of 46% between two ...
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Helium-Rich Stellar Atmosphere Models for B Stars [PDF]
International Astronomical Union Colloquium, 1985 AbstractThe hydrogen and helium line equivalent widths from stellar atmosphere models for early B stars are presented. The models, which range in helium number fraction from 0.10 to 0.85, result from the non-LTE statistical equilibrium code of Mihalas.
Andrew P. Odell, Stephen A. Voels
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Helium-rich stars in globular clusters: constraints for self-enrichment by massive stars [PDF]
Proceedings of the International Astronomical Union, 2009 AbstractGlobular clusters exhibit peculiar chemical patterns where Fe and heavy elements are constant inside a given cluster while light elements (Li to Al) show strong star-to-star variations. This pattern can be explained by self-pollution of the intracluster gas by the slow winds of fast rotating massive stars.
Thibaut Decressin +2 more
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Stars on the ascending helium giant branch
Astronomy & AstrophysicsHot subdwarf stars with masses above 0.8 M⊙ ascend the helium giant branch after the end of core helium burning, before entering the white dwarf cooling track or exploding as type Ib/c supernovae.
Pritzkuleit M. +5 more
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