Neutron Capture in Low‐Mass Asymptotic Giant Branch Stars: Cross Sections and Abundance Signatures

Arlandini, C.; Käppeler, F.; Wisshak, K.; Gallino, R.; Lugaro, Maria; Busso, M.; Straniero, O.

doi:10.1086/307938

Cited by 918 publications

(1,518 citation statements)

References 65 publications

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“…The ratio for UP is: [96]. A much larger value would cause conflicts with the Zr isotope systematics.…”

Section: Hfmentioning

confidence: 95%

“…The A+B grains are problematical as it is not possible to produce the high 26 Al/ 27 Al found in many B grains at the low T P when 12 C/ 13 C < ∼ 10, while maintaining C/O ≥ 1. 96 Mo is a pure s nuclide while 98,100 Mo are almost exclusively r process and 92,94 Mo are pure p process nuclei. The left panel shows the measured data [62] and the right panel shows the calculated values for an s process source [290].…”

Section: Conclusion and Major Problems -Potential And Realmentioning

confidence: 99%

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Short-lived nuclei in the early Solar System: Possible AGB sources

et al. 2006

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The abundances of short-lived radionuclides in the early solar system (ESS) are reviewed, as well as the methodology used in determining them. These results are compared with the inventory estimated for a uniform galactic production model. It is shown that, to within a factor of two, the observed abundances of 238 U, 235 U, 232 Th, 244 Pu, 182 Hf, 146 Sm, and 53 Mn are roughly compatible with long-term galactic nucleosynthesis. 129 I is an exception, with an ESS inventory much lower than expected from uniform production. The isotopes 107 Pd, 60 Fe, 41 Ca, 36 Cl, 26 Al, and 10 Be require late addition to the protosolar nebula. 10 Be is the product of energetic particle irradiation of the solar system as most probably is 36 Cl. Both of these nuclei appear to be present when 26 Al is absent. A late injection by a supernova (SN) cannot be responsible for most of the short-lived nuclei without excessively producing 53 Mn; it can however be the source of 53 Mn itself and possibly of 60 Fe. If a late SN injection is responsible for these two nuclei, then there remains the problem of the origin of 107 Pd and several other isotopes. Emphasis is given to an AGB star as a source of many of the nuclei, including 60 Fe; this possibility is explored with a new generation of stellar models. It is shown that if the dilution factor (i.e. the ratio of the contaminating mass to the solar parental cloud mass) is f 0 ∼ 4×10 −3 , a reasonable representation for many nuclei is obtained; this requires that ( 60 Fe/ 56 Fe) ESS ∼ 10 −7 to 2×10 −6 . The nuclei produced by an AGB source do not include 53 Mn, 10 Be or 36 Cl if it is very abundant. The role of irradiation is discussed with regard to 26 Al, 36 Cl and 41 Ca, and the estimates of bulk solar abundances of these isotopes are commented on. The conflict between various scenarios is emphasized as well as the current absence of an astrophysically plausible global interpretation for all the existing data. Examination of abundances for the actinides indicates that a quiescent interval of ∼ 10 8 years is required for actinide group production. This is needed in order to explain the data on 244 Pu and the new bounds on 247 Cm. Because this quiescent interval is not compatible with the 182 Hf data, a separate type of r-process event is needed for at least the actinides, distinct from the two types that have previously been identified. The apparent coincidence of the 129 I and trans-actinide time scales suggests that the last heavy r contribution was from an r-process that produced very heavy nuclei but without fission recycling so that the yields at Ba and below (including I) were governed by fission.

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“…The ratio for UP is: [96]. A much larger value would cause conflicts with the Zr isotope systematics.…”

Section: Hfmentioning

confidence: 95%

Section: Conclusion and Major Problems -Potential And Realmentioning

confidence: 99%

Short-lived nuclei in the early Solar System: Possible AGB sources

et al. 2006

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“…The key point of this figure is the possible role that each process plays in producing the abundance pattern of Solar-System r-process abundances (black dots [46]). The total abundance curve from all processes is shown as the black line on Figure 1.…”

Section: Current Models For the R-processmentioning

confidence: 99%

Origin of r-Process Elements and Galactic Chemodynamical Evolution

Mathews¹,

Shibagaki²,

Kajino³

2017

Proceedings of the 14th International Symposium on Nuclei in the Cosmos (NIC2016)

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It has been known for more than half a century that about half of the elements heavier than iron are produced via rapid neutron capture in the r-process. Indeed, the basic physical conditions for the r-process are well constrained by simple nuclear physics. In spite of this simplicity, however, the unambiguous identification of the site for the r-process nucleosynthesis has remained elusive. Parametrically, one can divide current models for the r-process into three scenarios roughly characterized by the number of neutron captures per seed nucleus (n/s). This parameter, in turn is the consequence of a variety of conditions such as time-scale, baryon density, average charge per baryon, and entropy. Here, we summarize various proposed sites for the r-process along with their short comings. Insights from a variety of nuclear physics measurements, astronomical observations, and models for galactic chemo-dynamical evolution are summarized. A paradigm is proposed whereby one may be able to quantify the relative contributions of each astrophysical site.

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“…Travaglio et al 2004a point to massive stars as likely site for this process. The mean residuals of Sr, Y, and Zr in the François et al 2007 sample (based on the Solar-system r-process abundances by Arlandini et al 1999) show that this LEPP process is responsible for 90-95% of the total abundance of these elements at [Ba/H] −4.3. In a recent paper by Montes et al 2007 the authors derive an abundance pattern of the LEPP and explore the possibility of a neutron-capture process.…”

Section: Evidence For a Lighter Element Primary Process (Lepp)mentioning

confidence: 99%

Detailed Nucleosynthesis Yields from the Explosion of Massive Stars

Fröhlich¹,

Fischer

Liebendörfer

et al. 2007

Proc. IAU

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Abstract. Despite the complexity and uncertainties of core collapse supernova simulations there is a need to provide correct nucleosynthesis abundances for the progressing field of galactic evolution and observations of low metallicity stars. Especially the innermost ejecta are directly affected by the explosion mechanism, i.e. most strongly the yields of Fe-group nuclei for which an induced piston or thermal bomb treatment will not provide the correct yields because the effect of neutrino interactions is not included.Recent observations of metal-poor halo stars support the suggested existence of a lighter element primary process (LEPP) which operates very early in the galaxy and is independent of the r-process. We present a candidate for the LEPP, the so-called νp-process.

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Neutron Capture in Low‐Mass Asymptotic Giant Branch Stars: Cross Sections and Abundance Signatures

Cited by 918 publications

References 65 publications

Short-lived nuclei in the early Solar System: Possible AGB sources

Short-lived nuclei in the early Solar System: Possible AGB sources

Origin of r-Process Elements and Galactic Chemodynamical Evolution

Detailed Nucleosynthesis Yields from the Explosion of Massive Stars

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