933 research outputs found
KADoNiS-: The astrophysical -process database
The KADoNiS- project is an online database for cross sections relevant to
the -process. All existing experimental data was collected and reviewed.
With this contribution a user-friendly database using the KADoNiS (Karlsruhe
Astrophysical Database of Nucleosynthesis in Stars) framework is launched,
including all available experimental data from (p,), (p,n),
(p,), (,), (,n) and (,p) reactions in
or close to the respective Gamow window with cut-off date of August 2012
(www.kadonis.org/pprocess).Comment: Proceedings Nuclear Data Conference 2013, published in Nuclear Data
Sheets 120 (2014) 19
Testing the role of SNe Ia for galactic chemical evolution of p-nuclei with two-dimensional models and with s-process seeds at different metallicities
Date of Acceptance: 07/11/2014The bulk of p isotopes is created in the "gamma processes" mainly by sequences of photodisintegrations and beta decays in explosive conditions in Type Ia supernovae (SNIa) or in core collapse supernovae (ccSN). The contribution of different stellar sources to the observed distribution of p-nuclei in the solar system is still under debate. We explore single degenerate Type Ia supernovae in the framework of two-dimensional SNIa delayed-detonation explosion models. Travaglio et al. discussed the sensitivity of p-nuclei production to different SNIa models, i.e., delayed detonations of different strength, deflagrations, and the dependence on selected s-process seed distributions. Here we present a detailed study of p-process nucleosynthesis occurring in SNIa with s-process seeds at different metallicities. Based on the delayed-detonation model DDT-a of TRV11, we analyze the dependence of p-nucleosynthesis on the s-seed distribution obtained from different strengths of the 13C pocket. We also demonstrate that 208Pb seed alone changes the p-nuclei production considerably. The heavy-s seeds (140 ≤A < 208) contribute with about 30%-40% to the total light-p nuclei production up to 132Ba (with the exception of 94Mo and 130Ba, to which the heavy-s seeds contribute with about 15% only). Using a Galactic chemical evolution code from Travaglio et al., we study the contribution of SNIa to the solar stable p-nuclei. We find that explosions of Chandrasekhar-mass single degenerate systems produce a large amount of p-nuclei in our Galaxy, both in the range of light (A ≤ 120) and heavy p-nuclei, at almost flat average production factors (within a factor of about three). We discussed in details p-isotopes such as 94Mo with a behavior diverging from the average, which we attribute to uncertainties in the nuclear data or in SNIa modeling. Li et al. find that about 70% of all SNeIa are normal events. If these are explained in the framework of explosions of Chandrasekhar-mass white dwarfs resulting from the single-degenerate progenitor channel, we find that they are responsible for at least 50% of the p-nuclei abundances in the solar system.Peer reviewedFinal Accepted Versio
New Stellar Cross Sections and The "Karlsruhe Astrophysical Database of Nucleosynthesis in Stars"
Since April 2005 a regularly updated stellar neutron cross section
compilation is available online at http://nuclear-astrophysics.fzk.de/kadonis.
This online-database is called the "Karlsruhe Astrophysical Database of
Nucleosynthesis in Stars" project and is based on the previous Bao et al.
compilation from the year 2000. The present version \textsc{KADoNiS} v0.2
(January 2007) includes recommended cross sections for 280 isotopes between
H and Po and 75 semi-empirical estimates for isotopes without
experimental information. Concerning stellar cross sections of the
32 stable, proton-rich isotopes produced by the process experimental
information is only available for 20 isotopes, but 9 of them have rather large
uncertainties of 9%. The first part of a systematic study of stellar
cross sections of the -process isotopes Se, Sr,
Pd, Te, Ba, Ba, Dy, and Hf is
presented. In another application \textsc{KADoNiS} v0.2 was used for an
modification of a reaction library of Basel university. With this modified
library -process network calculations were carried out and compared to
previous results.Comment: Proceedings "International Conference on Nuclear Data for Science and
Technology 2007", Nice/ Franc
The Karlsruhe Astrophysical Database of Nucleosynthesis in Stars Project - Status and Prospects
The KADoNiS (Karlsruhe Astrophysical Database of Nucleosynthesis in Stars) project is an astrophysical online database for cross sections relevant for nucleosynthesis in the s process and the γ process. The s-process database (http://www.kadonis.org) was started in 2005 and is presently facing its 4th update (KADoNiS v1.0). The γ-process database (KADoNiS-p, http://www.kadonis.org/pprocess) was recently revised and re-launched in March 2013. Both databases are compilations for experimental cross sections with relevance to heavy ion nucleosynthesis. For the s process recommended Maxwellian averaged cross sections for kT=5-100 keV are given for more than 360 isotopes between 1H and 210Bi. For the γ-process database all available experimental data from (p, γ), (p, n), (p, α), (α, γ), (α, n), and (α, p) reactions between 70Ge and 209Bi in or close to the respective Gamow window were collected and can be compared to theoretical predictions. The aim of both databases is a quick and user-friendly access to the available data in the astrophysically relevant energy regions. © 2014 Elsevier Inc.Peer reviewe
Type Ia Supernovae as Sites of p-process: Two-Dimensional Models Coupled to Nucleosynthesis
We explore SNe Ia as p-process sites in the framework of two-dimensional SN
Ia delayed detonation and pure deflagration models. The WD precursor is assumed
to have reached the Chandrasekhar mass in a binary system by mass accretion
from a giant/main sequence companion. We use enhanced s-seed distributions,
obtained from a sequence of thermal pulse instabilities both in the AGB phase
and in the accreted material. We apply the tracer-particle method to
reconstruct the nucleosynthesis by the thermal histories of Lagrangian
particles, passively advected in the hydrodynamic calculations. For each
particle we follow the explosive nucleosynthesis with a detailed network for
all isotopes up to 209Bi. We find that SNe Ia can produce a large amount of
p-nuclei, both the light p-nuclei below A=120 and the heavy-p nuclei, at quite
flat average production factors, tightly related to the s-process seed
distribution. For the first time, we find a stellar source able to produce
both, light and heavy p-nuclei almost at the same level as 56Fe, including the
very debated neutron magic 92,94Mo and 96,98Ru. We also find that there is an
important contribution from p-process nucleosynthesis to the s-only nuclei
80Kr, 86Sr, to the neutron magic 90Zr, and to the neutron-rich 96Zr. Finally,
we investigate the metallicity effect on p-process. Starting with different
s-process seed distributions, for two metallicities Z = 0.02 and Z = 0.001,
running SNe Ia models with different initial composition, we estimate that SNe
Ia can contribute to, at least, 50% of the solar p-process composition.Comment: 62 pages, 14 figures, 5 tables, ApJ in pres
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