Oxygen and light-element synthesis by neutron-capture reactions in metal-free and extremely metal-poor AGB stars

@article{Nishimura2009OxygenAL,
  title={Oxygen and light-element synthesis by neutron-capture reactions in metal-free and extremely metal-poor AGB stars},
  author={Takanori Nishimura and Masayuki Aikawa and Takuma Suda and Masayuki Y. Fujimoto},
  journal={Publications of the Astronomical Society of Japan},
  year={2009},
  volume={61},
  pages={909-929}
}
The metal-free (Population III: Pop. III) and extremely metal-poor (EMP) stars of low-and intermediate-masses experience mixing of hydrogen into the helium convection during the early TP-AGB phase, differently from the metal-rich stars. We have studied nucleosynthesis in the helium convective zone with 13C formed from mixed protons as a neutron source by using a nuclear network from H through S. In the absence or scarcity of pristine metals, neutron-recycling reactions, l2C (n, γ) 13C (α, n… Expand
The s-Process Nucleosynthesis in Extremely Metal-Poor Stars as the Generating Mechanism of Carbon Enhanced Metal-Poor Stars
The origin of carbon-enhanced metal-poor (CEMP) stars plays a key role in characterising the formation and evolution of the first stars and the Galaxy since the extremely-poor (EMP) stars with [Fe/H]Expand
FORMATION AND EVOLUTION OF CARBON-ENHANCED METAL-POOR STARS
Carbon-enhanced metal-poor (CEMP) stars play a key role in characterising the star formation history of the Galactic halo. In particular, most stars show carbon enhancement among the lowestExpand
A new model for the origin of very metal poor stars and their chemical composition
The genesis and chemical patterns of the metal-poor stars in the galactic halo remain an open question. Current models do not seem to give a satisfactory explanation for the observed abundances ofExpand
Chemical analysis of the ninth magnitude carbon-enhanced metal-poor star BD+44°493
We present detailed chemical abundances for the bright carbon-enhanced metal-poor (CEMP) star BD+44°493, previously reported on by Ito et al. Our measurements confirm that BD+44°493 is an extremelyExpand
The most iron-deficient stars as the polluted population III stars
We investigate the origin of the most iron-poor stars including SMSS J031300.36-670839.3 with [Fe/H] < -7.52. We compute the change of surface metallicity of stars with the accretion of interstellarExpand
Evolution of low- and intermediate-mass stars with [Fe/H]≤− 2.5
We present extensive sets of stellar models for 0.8 9.0M⊙ in mass and 5 6 [Fe/H] 6 2 and Z = 0 in metallicity. The present work focuses on the evolutionary characteristics of hydrogen mixing into theExpand
Abundance Profiling of Extremely Metal-Poor Stars and Supernova Properties in the Early Universe
After the Big Bang nucleosynthesis, the first heavy element enrichment in the Universe was made by a supernova (SN) explosion of a population (Pop) III star (Pop III SN). The abundance ratios ofExpand
FORMATION HISTORY OF METAL-POOR HALO STARS WITH HIERARCHICAL MODEL AND THE EFFECT OF ISM ACCRETION ON THE MOST METAL-POOR STARS
We investigate the star formation and chemical evolution in the early universe by considering the merging history of the Galaxy in thecold dark matter scenario according to the extended Press-Expand
EXTREMELY METAL-POOR STARS AND A HIERARCHICAL CHEMICAL EVOLUTION MODEL
Early phases of the chemical evolution of the Galaxy and formation history of extremely metal-poor (EMP) stars are investigated using hierarchical galaxy formation models. We build a merger tree ofExpand
Chemical Abundances and Dust in the Halo Planetary Nebula K648 in M15: Its Origin and Evolution based on an Analysis of Multiwavelength Data
We report an investigation of the extremely metal-poor and C-rich planetary nebula (PN) K648 in the globular cluster M15 using the UV to far-IR data obtained using the Subaru, HST, FUSE, Spitzer, andExpand
...
1
2
...

References

SHOWING 1-10 OF 72 REFERENCES
Nucleosynthesis of s-elements in zero-metal AGB stars
Contrary to previous expectations, recent evolutionary models of zero-metallicity stars show that the development of mixing episodes at the beginning of the AGB phase allows low- andExpand
The Origin of Carbon Enhancement and the Initial Mass Function of Extremely Metal-poor Stars in the Galactic Halo
It is known that the carbon-enhanced, extremely metal-poor (CEMP) stars constitute a substantial proportion of the extremely metal-poor (EMP) stars of the Galactic halo, and a by far largerExpand
First stars VI - Abundances of C, N, O, Li, and mixing in extremely metal-poor giants. Galactic evolution of the light elements
We have investigated the poorly-understood origin of nitrogen in the early Galaxy by determining N abundances from the NH band at 336 nm in 35 extremely metal-poor halo giants, with carbon and oxygenExpand
A Search for Nitrogen-enhanced Metal-poor Stars*
Theoretical models of very metal-poor intermediate-mass asymptotic giant branch (AGB) stars predict a large overabundance of primary nitrogen. The very metal-poor, carbon-enhanced, s-process-richExpand
First-generation black-hole-forming supernovae and the metal abundance pattern of a very iron-poor star
TLDR
It is inferred that the first-generation supernovae came mostly from explosions of ∼20–130 M[circdot] stars; some of these produced iron-poor but carbon- and oxygen-rich ejecta, and low-mass second-generation stars, like HE0107–5240, could form because the carbon and oxygen provided pathways for the gas to cool. Expand
The Origin of Extremely Metal-poor Carbon Stars and the Search for Population III.
TLDR
It is shown that low-mass, extremely metal-poor stars evolve into carbon stars along paths that are quite different from those followed by more metal-rich stars of younger populations, allowing us, in principle, to distinguish the brightest survivors of the first generations of stars formed in the universe (Population III carbon stars) from stars belonging to younger populations. Expand
Nucleosynthetic signatures of the first stars
TLDR
The discovery of HE1327–2326 is reported, a subgiant or main-sequence star with an iron abundance about a factor of two lower than that of HE0107–5240, suggesting a similar origin of the abundance patterns. Expand
A stellar relic from the early Milky Way
TLDR
This work reports the discovery of a low-mass star with an iron abundance as low as 1/200,000 of the solar value, which suggests that population III stars could still exist and that the first generation of stars also contained long-livedLow-mass objects. Expand
First stars X. The nature of three unevolved Carbon-Enhanced Metal-Poor stars ⋆
Context. On the order of 20% of the very metal-poor stars in the Galaxy exhibit large carbon enhancements. It is important to establish which astrophysical sites and processes are responsible for theExpand
Is HE 0107–5240 A Primordial Star? The Characteristics of Extremely Metal-Poor Carbon-Rich Stars
We discuss the origin of HE 0107-5240, which, with a metallicity of [Fe/H] = -5.3, is the most iron-poor star yet observed. Its discovery has an important bearing on the question of the observabilityExpand
...
1
2
3
4
5
...