Related papers: $^{180}$Ta production in the classical s-process
Ground- and space-based observations of stellar heavy element abundances are providing a clearer picture of the chemical evolution of the Galaxy. A large number of (r)apid and (s)low neutron capture process elements, including the first…
We investigate the nucleosynthesis in a massive star of 70 M_solar with solar metallicity in the main sequence stage. The helium core mass after hydrogen burning corresponds to 32 M_solar. Nucleosynthesis calculations have been performed…
Cometary studies suggest that the organic composition of the early Solar Nebula was rich in complex nitrile species such a CH$_3$CN. Recent ALMA detections in protoplanetary disks suggest that these species may be common during planet and…
We discuss the hard X-ray properties of the Seyfert galaxy Ton S 180, based upon the analysis of ASCA data. We find the X-ray flux varied by a factor ~2 on a time scale of a few thousand seconds. The source showed significantly higher…
The s-process, a production mechanism based on slow-neutron capture during stellar evolution, is the origin of about half the elements heavier than iron. Abundance predictions for s-process nucleosynthesis depend strongly on the relevant…
Using recently calculated yields for Type II supernovae, along with models for chemical evolution and the distribution of mass in the interstellar medium, the current abundances and spatial distributions of two key gamma-ray…
Nuclear interactions of ions accelerated at the surface of flaring stars can produce fresh isotopes in stellar atmospheres. Although this nucleosynthesis is not significant for the chemical evolution of the Galaxy, it can be important for a…
We have measured the Li abundance of 18 stars with -2 <~ [Fe/H] ~< -1 and 6000 K <~ Teff <~ 6400 K, a parameter range that was poorly represented in previous studies. We examine the Galactic chemical evolution (GCE) of this element,…
We study the synthesis of lithium isotopes in the hot tori formed around stellar mass black holes by accretion of the companion star. We find that sizable amounts of both stable isotopes 6Li and 7Li can be produced, the exact figures…
The $^{58}$Ni $(n,\gamma)$ cross section has been measured at the neutron time of flight facility n_TOF at CERN, in the energy range from 27 meV up to 400 keV. In total, 51 resonances have been analyzed up to 122 keV. Maxwellian averaged…
We present the abundances of the intermediate elements obtained by performing a stacked analysis of all the galaxy clusters in the archive of the X-ray telescope ASCA. We give the abundances of Fe, Si, S, and Ni as a function of cluster…
The s-process in AGB stars produces elements with atomic mass numbers $A\gtrsim60$ through successive neutron captures and beta decays. In stellar environments where the s-process occurs, neutrons quickly thermalize, adopting a…
We derive the abundance of 19 elements in a sample of 64 stars with fundamental parameters very similar to solar, which minimizes the impact of systematic errors in our spectroscopic 1D-LTE differential analysis, using high-resolution…
The 62Ni(n,gamma)63Ni(t_1/2=100+-2 yrs) reaction plays an important role in the control of the flow path of the slow neutron-capture (s-) nucleosynthesis process. We have measured for the first time the total cross section of this reaction…
We consider the equilibration of the 'wrong--helicity' Dirac neutrino states $\nu_{+}$ and $\overline\nu_{-}$ in the early Universe via weak interactions and calculate carefully the thermally averaged production rate, taking into account…
Rotation was shown to have a strong impact on the structure and light element nucleosynthesis in massive stars. In particular, models including rotation can reproduce the primary nitrogen observed in halo extremely metal-poor (EMP) stars.…
50% of the heavy element abundances are produced via slow neutron capture reactions in different stellar scenarios. The underlying nucleosynthesis models need the input of neutron capture cross sections. One of the fundamental signatures…
In this paper we present a large-scale sensitivity study of reaction rates in the main component of the $s$ process. The aim of this study is to identify all rates, which have a global effect on the $s$ process abundance distribution and…
A high-statistics experiment on a deuterium target was performed using a real photon beam with energies up to 3.6 GeV at the CLAS detector of Jefferson Lab. The reaction reported here is for $\gamma d \to p K^- K^+ n$ where the neutron was…
Despite much effort in the past decades, the C-burning reaction rate is uncertain by several orders of magnitude, and the relative strength between the different channels 12C(12C,alpha)20Ne, 12C(12C,p)23Na and 12C(12C,n)23Mg is poorly…