J

Arnould, Michel; Zubini, Fabio

doi:10.1007/978-94-011-8080-1_10

Cited by 33 publications

(43 citation statements)

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“…The p-process site should be rich in hydrogen, with proton density ≥10 2 g/cm 3 , at temperatures of T = 2−3 × 10 9 K. This process site is most likely related to SN II, according to Arnould (1976), Woosley & Howard (1978, and references therein), Arnould et al (1992), and Rayet et al (1993) or the explosion of a moderately massive white dwarf due to the accretion of He-rich matter (Goriely et al 2005, and references therein). A quantitative study of the p-process is presented in Rayet et al (1995).…”

Section: S- R- and P-processesmentioning

confidence: 99%

Analysis of 26 barium stars

Allen

Barbuy

2006

A&A

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Context. Barium stars show enhanced abundances for the slow neutron capture (s-process) heavy elements, so they are suitable objects for studying s-process elements. Aims. The aim of this work is to quantify the contributions of the s-, r-, and p-processes for the total abundance of heavy elements from abundances derived for a sample of 26 barium stars. The abundance ratios between these processes and neutron exposures were studied. Methods. The abundances of the sample stars were compared to those of normal stars, thus identifying the fraction relative to the main component of the s-process. Results. The fittings of the σN curves (neutron-capture cross-section times abundance, plotted against atomic mass number) for the sample stars suggest that the material from the companion asymptotic giant branch star had approximately the solar isotopic composition as concerns fractions of abundances relative to the s-process main component. The abundance ratios of heavy elements, hs, ls, and s and the computed neutron exposure are similar to those of post-AGB stars. For some sample stars, an exponential neutron exposure fits the observed data well, whereas a single neutron exposure provides a better fit for others. Conclusions. The comparison of barium and AGB stars supports the hypothesis of binarity for the barium star formation. Abundances of r-elements that are part of the s-process path in barium stars are usually higher than those in normal stars, so barium stars also seemed to be enriched in r-elements, although to a lower degree than s-elements. No dependence on luminosity classes was found in the abundance-ratio behaviour among the dwarfs and giants of the sample of barium stars.

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Section: S- R- and P-processesmentioning

confidence: 99%

Analysis of 26 barium stars

Allen

Barbuy

2006

A&A

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“…It is known that the mass region of the gprocess layers depends on astrophysical conditions and is shifted to the outer layers as the explosion energy or the mass increases (Arnould 1976;Woosley & Howard 1978;Rayet et al 1990Rayet et al , 1995. This shift also is confirmed in our calculations and contributes to the universality.…”

Section: Calculations and Discussionmentioning

confidence: 98%

“…The origin of the p-nuclei has been discussed over the last 50 years, and many nucleosynthetic processes have been proposed (Burbidge et al 1957;Audouze 1970;Arnould 1976;Woosley & Howard 1978;Woosley et al 1990;Howard et al 1991;Rayet et al 1995;Schatz et al 2001;Prunet et al 2005;Fröhlich et al 2006;Wanajo 2006). Arnould (1976) proposed the p-process in presupernova phases, and Woosley & Howard (1978) proposed the g-process in supernovae (SNe). In these pioneering works, the p-nuclei are synthesized mainly by photodisintegration reactions from preexisting nuclei affected by the s-process in an earlier evolutionary state of progenitors, or by the r-process in a previous generation stars.…”

Section: Introductionmentioning

confidence: 98%

Principle of Universality of γ-Process Nucleosynthesis in Core-Collapse Supernova Explosions

Hayakawa¹,

Iwamoto²,

Kajino³

et al. 2006

ApJ

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Using core-collapse supernova explosion models, we investigate the principle of the universality of the gprocess, according to which the s/p abundance ratios produced by individual nucleosynthesis episode are almost constant over a wide range of atomic number. The universality originates from the shift of the g-process layers, the independence of the s/p abundance ratios of the nuclear reactions, and the weak s-process in presupernovae. Our calculations further suggest an extended universality in which the s/p ratios in the g-process layers are not only constant but also centered around a specific value of 3. To verify this, we propose an astronomical observation of indium isotopic abundance fractions.

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“…Subsequent studies based on the carbon deflagration model of Nomoto, Thielemann, & Yokoi (1984) found similar problems (Kusakabe, Iwamoto & Nomoto 2005). This moved the focus of studying the origin of p nuclides to their production in the O/Ne shells of exploding massive stars (corecollapse supernovae, ccSNe), where also photodisintegrations act during the passage of the supernova shock (Arnould 1976;Woosley & Howard 1978;Hoffman et al 1996). Also this site, however, cannot produce all p nuclides in solar proportions.…”

Section: Introductionmentioning

confidence: 99%

Uncertainties in the production of p nuclides in thermonuclear supernovae determined by Monte Carlo variations

Nishimura

Rauscher

Hirschi

et al. 2017

Monthly Notices of the Royal Astronomical Society

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Thermonuclear supernovae originating from the explosion of a white dwarf accreting mass from a companion star have been suggested as a site for the production of p nuclides. Such nuclei are produced during the explosion, in layers enriched with seed nuclei coming from prior strong s processing. These seeds are transformed into protonricher isotopes mainly by photodisintegration reactions. Several thousand trajectories from a 2D explosion model were used in a Monte Carlo approach. Temperaturedependent uncertainties were assigned individually to thousands of rates varied simultaneously in post-processing in an extended nuclear reaction network. The uncertainties in the final nuclear abundances originating from uncertainties in the astrophysical reaction rates were determined. In addition to the 35 classical p nuclides, abundance uncertainties were also determined for the radioactive nuclides ), important for Galactic Chemical Evolution studies. Uncertainties found were generally lower than a factor of 2, although most nucleosynthesis flows mainly involve predicted rates with larger uncertainties. The main contribution to the total uncertainties comes from a group of trajectories with high peak density originating from the interior of the exploding white dwarf. The distinction between low-density and high-density trajectories allows more general conclusions to be drawn, also applicable to other simulations of white dwarf explosions.

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J

Cited by 33 publications

References 0 publications

Analysis of 26 barium stars

Analysis of 26 barium stars

Principle of Universality of γ-Process Nucleosynthesis in Core-Collapse Supernova Explosions

Uncertainties in the production of p nuclides in thermonuclear supernovae determined by Monte Carlo variations

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