Zobrazeno 1 - 10
of 1 044
pro vyhledávání: '"Stellar nucleosynthesis"'
Autor:
Chiaki Kobayashi, Andrea Ferrara
Publikováno v:
The Astrophysical Journal Letters, Vol 962, Iss 1, p L6 (2024)
We interpret the peculiar supersolar nitrogen abundance recently reported by the James Webb Space Telescope observations for GN-z11 ( z = 10.6) using our state-of-the-art chemical evolution models. The observed CNO ratios can be successfully reproduc
Externí odkaz:
https://doaj.org/article/4747eb45cada497b9d52c4fcaa85540e
Autor:
Chemseddine Ananna, Lucia Barbieri, Axel Boeltzig, Matteo Campostrini, Fausto Casaburo, Alessandro Compagnucci, Laszlo Csedreki, Riccardo Maria Gesue, Jordan Marsh, Daniela Mercogliano, Denise Piatti, Duncan Robb, Ragandeep Singh Sidhu, Jakub Skowronski
Publikováno v:
Universe, Vol 10, Iss 5, p 228 (2024)
Nuclear reactions are responsible for the chemical evolution of stars, galaxies and the Universe. Unfortunately, at temperatures of interest for nuclear astrophysics, the cross-sections of the thermonuclear reactions are in the pico- femto-barn range
Externí odkaz:
https://doaj.org/article/a20f9a40bc8d4d2e8b0b400bde8db32a
Autor:
Panagiota Giannaka, Theocharis Kosmas
Publikováno v:
Particles, Vol 5, Iss 3, Pp 377-389 (2022)
The stellar electron capture on nuclei is an essential, semi-leptonic process that is especially significant in the central environment of core-collapse supernovae and in the explosive stellar nucleosynthesis. In this article, on the basis of the ori
Externí odkaz:
https://doaj.org/article/9efa8b100aa44162a64cb745e8fe31ac
Autor:
S. K. Jeena, Projjwal Banerjee
Publikováno v:
The Astrophysical Journal, Vol 975, Iss 1, p 108 (2024)
Very metal-poor (VMP) stars ([Fe/H] ≤ −2) that have subsolar values of [X/Fe] for α elements such as Mg, Si, and Ca, are referred to as α -poor VMP stars. They are quite rare among VMP stars and are thought to have formed from gas enriched pred
Externí odkaz:
https://doaj.org/article/18b339c215af48bcbb6e37d3a3ca96da
Autor:
G. L. Guardo, L. Lamia, J. P. Fernández-García, S. Piskor, M. La Cognata, G. D’Agata, S. Palmerini, D. Vescovi, V. Burjan, R. J. deBoer, V. Kroha, D. Lattuada, J. Mrazek, A. A. Oliva, R. G. Pizzone, G. G. Rapisarda, S. Romano, M. L. Sergi, R. Spartá, A. Tumino
Publikováno v:
The Astrophysical Journal, Vol 975, Iss 1, p 32 (2024)
Indirect methods have proven to be a complementary approach for extending our knowledge of nuclear structure and low-energy cross sections. Among these, the neutron-induced reaction cross sections appear to be of particular interest since their role
Externí odkaz:
https://doaj.org/article/d4bc6305f7224b5898d1e195b0c7c0b8
Publikováno v:
The Astrophysical Journal, Vol 973, Iss 2, p 122 (2024)
The scale of α -element yields is difficult to predict from theory because of uncertainties in massive star evolution, supernova physics, and black hole formation, and it is difficult to constrain empirically because the impact of higher yields can
Externí odkaz:
https://doaj.org/article/9710525c1d0346d3809a94acae78b5e5
Publikováno v:
The Astrophysical Journal, Vol 973, Iss 2, p 93 (2024)
The ^18 O( p , α ) ^15 N reaction is of particular importance for influencing the abundances of key isotopes such as ^19 F, ^18 O, and ^15 N. Peculiar abundances for these nuclei are observed from spectra or meteorite grains originating in asymptoti
Externí odkaz:
https://doaj.org/article/4c6268b4ca534654a2206ba5a41b4380
Publikováno v:
The Astrophysical Journal Supplement Series, Vol 272, Iss 2, p 34 (2024)
A novel methodology is developed to extract accurate skeletal reaction models for nuclear combustion. Local sensitivities of isotope mass fractions with respect to reaction rates are modeled based on the forced optimally time-dependent (f-OTD) scheme
Externí odkaz:
https://doaj.org/article/bce07243777d40b798c6ed706083409b
Publikováno v:
The Astrophysical Journal Supplement Series, Vol 272, Iss 1, p 15 (2024)
We present an extension of the set of models published in Limongi & Chieffi (2018) at metallicity 2 times solar, i.e., [Fe/H] = 0.3. The key physical properties of these models at the onset of core collapse are mainly due to the higher mass loss trig
Externí odkaz:
https://doaj.org/article/fcc740621fea434184b07cb606ece4e2
Autor:
N. D. Nevill, P. A. Bland, D. W. Saxey, W. D. A. Rickard, P. Guagliardo, N. E. Timms, L. V. Forman, L. Daly, S. M. Reddy
Publikováno v:
The Astrophysical Journal, Vol 964, Iss 2, p 151 (2024)
We have discovered a presolar olivine from ALH 77307 with the highest ^25 Mg isotopic composition measured in a silicate to date ( δ ^25 Mg = 3025.1‰ ± 38.3‰). Its isotopic compositions challenge current stellar models, with modeling of magnesi
Externí odkaz:
https://doaj.org/article/afd77b28cfff4e20b32fa4a794ed4cec