scholarly journals The 19F(α, p)22Ne and 23Na(p,α)20Ne reaction in AGB nucleosynthesis via THM

2018 ◽  
Vol 184 ◽  
pp. 02003 ◽  
Author(s):  
G. D’Agata ◽  
R. G. Pizzone ◽  
M. La Cognata ◽  
I. Indelicato ◽  
C. Spitaleri ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Energy Range ◽  
Globular Clusters ◽  
Trojan Horse ◽  
The Other ◽  
Agb Stars ◽  
Mixing Processes ◽  
Trojan Horse Method ◽  
Three Body ◽  
The Universe

In AGB environment, fluorine and sodium abundances are still matter of debate. About 19F (only stable isotope of fluorine), its abundance in the universe is strictly related to standard and extra-mixing processes taking place inside AGB-stars, that are considered to be the most important sites for its production. Nevertheless the way in which it is destroyed is far from being well understood. On the other hand, 23Na presence in Globular Clusters, along with is well-known anticorrelation with oxygen has made clear that this element must be produced in previous generations stars, and intermediatemass AGB stars are one of the possible candidates for its production. For this reason we studied the 19F(α,p)22Ne and 23Na(p,α)20Ne reactions in the energy range of relevance for astrophysics via the Trojan Horse Method (THM), using the three-body reactions 6Li(19F, p22Ne)d and 23Na(d, pn)20Ne.

scholarly journals Study of the neutron induced reaction 17O(n,α)14C at astrophysical energies via the Trojan Horse Method

2020 ◽  
Vol 227 ◽  
pp. 02007
Author(s):  
A. A. Oliva ◽  
L. Lamia ◽  
G. L. Guardo ◽  
C. Spitaleri ◽  
S. Cherubini ◽  
...  
Keyword(s):  
Energy Range ◽  
Center Of Mass ◽  
Trojan Horse ◽  
Trojan Horse Method ◽  
Three Body ◽  
The Universe ◽  
Induced Reaction

Neutron induced reactions are fundamental for the nucleosynthesis of elements in the universe. Indeed, to correctly study the reactions involved in the well-known s-process in stars, which produce about half of the elements beyond the iron peak, it is mandatory to know the neutron abundance available in those stars. The 17O(n, a)14C reaction is one of the so-called “neutron poisons” for the pro- cess and it could play an important role in the balance of the neutron abundance. The reaction is therefore investigated in the energy range of astrophysical inter- est between 0 and 350 keV in the center of mass by applying the Trojan Horse Method to the three body reaction 2H(17O, a14C)H.

Unexpectedly high formation rate of merging binary black holes in open clusters

2019 ◽  
Vol 14 (S351) ◽  
pp. 204-207
Author(s):  
Jun Kumamoto ◽  
Michiko S. Fujii ◽  
Ataru Tanikawa
Keyword(s):  
Black Holes ◽  
Globular Clusters ◽  
Formation Rate ◽  
Mass Function ◽  
Open Clusters ◽  
Binary Black Holes ◽  
Initial Cluster ◽  
Three Body ◽  
The Universe ◽  
Hubble Time

AbstractGravitational wave direct detections suggest that 30 M⊙ binary black holes (BBHs) commonly exist in the universe. One possible formation scenario of such BBHs is dynamical three-body encounters in dense star clusters. We performed a series of direct N-body simulations with a mass of 2500 and 10000 M⊙ and found a new channel for the formation of BBHs which is dominant in open clusters. In open clusters, the core-collapse time is shorter than in globular clusters, and therefore massive main-sequence (MS) binaries can form before they evolve to BHs. These MS binaries experience common envelope evolution and evolve to hard BBHs, which can merge within the Hubble time. The number of BBH mergers per unit mass obtained from our simulations reached 20–50 % of that for globular clusters, assuming an initial cluster mass function. Thus, open clusters can be a dominant formation site of hard BBHs.

scholarly journals Study of 3He(n,p)3H reaction at cosmological energies with trojan horse method

2020 ◽  
Vol 227 ◽  
pp. 02013 ◽  
Author(s):  
C. Spampinato ◽  
R.G. Pizzone ◽  
R. Spartà ◽  
M. Couder ◽  
W. Tan ◽  
...  
Keyword(s):  
Energy Range ◽  
Big Bang ◽  
Trojan Horse ◽  
Big Bang Nucleosynthesis ◽  
Preliminary Results ◽  
Trojan Horse Method ◽  
Gamow Energy ◽  
The Big Bang

In the network of reactions present in the Big Bang nucleosynthesis, the 3He(n, p)3H has an important role which impacts the final 7Li abundance. The Trojan Horse Method (THM) has been applied to the 3He(d, pt)H reaction in order to extract the astrophysical S(E)-factor of the 3He(n, p)3H in the Gamow energy range. The experiment will be described in the present work together with the first preliminary results.

scholarly journals Trojan Horse Method experiments with radioactive ion beams

2018 ◽  
Vol 184 ◽  
pp. 01008
Author(s):  
Marisa Gulino ◽  
Silvio Cherubini ◽  
Giuseppe Gabriele Rapisarda ◽  
Shigeru Kubono ◽  
Livio Lamia ◽  
...  
Keyword(s):  
Reaction Cross Section ◽  
Reaction Cross ◽  
Ion Beams ◽  
Trojan Horse ◽  
Radioactive Ion Beams ◽  
Final State ◽  
Low Intensity ◽  
Trojan Horse Method ◽  
Three Body ◽  
Suppression Effects

The Trojan Horse Method (THM) is an indirect method that allows to get information about a two body reaction cross-section even at very low energy, avoiding the suppression effects due to the presence of the Coulomb barrier. The method requires a very accurate measurement of a three body reaction in order to reconstruct the whole kinematics and discriminate among different reaction mechanisms that can populate the same final state. These requirements hardly match with the typical low intensity and large divergence of radioactive ion beams (RIBs), and experimental improvements are mandatory for the applicability of the method. The first reaction induced by a radio activeion beam studied by applying the THM was the 18F(p,α)15O. Two experiments were performed in two different laboratories and using different experimental set-ups. The two experiments will be discussed and some results will be presented.

scholarly journals Binaries in Globular Clusters

1998 ◽  
Vol 11 (2) ◽  
pp. 616-621 ◽  
Author(s):  
S. L. W. Mcmillan ◽  
C. Pryor ◽  
E. S. Phinney
Keyword(s):  
Kinetic Energy ◽  
Globular Cluster ◽  
Binary Stars ◽  
Formation Process ◽  
Globular Clusters ◽  
The Other ◽  
Energy Distributions ◽  
Other Hand ◽  
Mass Segregation ◽  
Three Body

Binary stars in a globular cluster (hereafter, GC) may be primordial (i.e. formed along with the cluster), or the result of cluster dynamics. “Dynamical” binaries can result from conservative three-body encounters (e.g. Spitzer, 1987) if a third star can carry away enough kinetic energy to leave two others bound, or from dissipative two-body encounters, if two stars happen to pass within a few stellar radii of one other (Fabian, Pringle, & Rees, 1975). Such non-primordial systems are likely to be found primarily in evolved GC cores, both because conditions are more favorable for making them there, and because of mass segregation. Knowledge of the formation process allows reasonable estimates to be made of their mass and energy distributions. The initial spatial, mass, and energy distributions of primordial binaries, on the other hand, are largely unknown.

The 19F(α, p)22Ne Reaction at Energies of Astrophysical Relevance by Means of the Trojan Horse Method and Its Implications in AGB Stars

2018 ◽  
Vol 860 (1) ◽  
pp. 61 ◽  
Author(s):  
G. D’Agata ◽  
R. G. Pizzone ◽  
M. La Cognata ◽  
I. Indelicato ◽  
C. Spitaleri ◽  
...  
Keyword(s):  
Trojan Horse ◽  
Agb Stars ◽  
Trojan Horse Method

scholarly journals The Trojan Horse Method in Nuclear Astrophysics

2018 ◽  
Vol 184 ◽  
pp. 01016
Author(s):  
Aurora Tumino ◽  
Claudio Spitaleri ◽  
Silvio Cherubini ◽  
Giuseppe D’Agata ◽  
Guardo Giovanni Luca ◽  
...  
Keyword(s):  
Cross Section ◽  
Charged Particles ◽  
Nuclear Astrophysics ◽  
Trojan Horse ◽  
Trojan Horse Method ◽  
Basic Features ◽  
Three Body

The Trojan Horse Method (THM) represents the indirect way to measure reactions between charged particles at astrophysical energies. This is done by measuring the quasi free cross section of a suitable three body process. The basic features of the THM will be presented together with some applications to demonstrate its practical use.

scholarly journals An overall picture of EMP stars using the stellar abundances for galactic archaeology (SAGA) database

2009 ◽  
Vol 5 (S265) ◽  
pp. 90-93
Author(s):  
Takuma Suda ◽  
Shimako Yamada ◽  
Yutaka Katsuta ◽  
Chikako Ishizuka ◽  
Yutaka Komiya ◽  
...  
Keyword(s):  
Early Phase ◽  
Globular Clusters ◽  
The Other ◽  
Stellar Abundances ◽  
Mixing Processes ◽  
Lithium Abundance ◽  
Other Hand ◽  
The Galaxy ◽  
Order Of Magnitude ◽  
Red Giant

AbstractWe explore the general characteristics of extremely metal-poor (EMP) stars in the Galaxy using the Stellar Abundances for Galactic Archaeology (SAGA) database (Suda et al. 2008, PASJ, 60, 1159). The overall trend of EMP stars suggests that there are at least two types of extra mixing to change the surface abundances of EMP stars. One is to deplete lithium abundance during the early phase of giant branch and another is to decrease C/N ratio by one order of magnitude during the red giant branch or AGB phase. On the other hand, these mixing processes are different from those suggested in the Galactic globular clusters because of the different relations between O, Na, Mg, and Al abundances.

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