Results 51 to 60 of about 66,893 (303)

Presupernova Evolution and Explosive Nucleosynthesis of Rotating Massive Stars in the Metallicity Range −3 ≤ [Fe/H] ≤ 0 [PDF]

Astrophysical Journal Supplement Series, 2018
We present a new grid of presupernova models of massive stars extending in mass between 13 and 120 , covering four metallicities (i.e., [Fe/H] = 0, −1, −2, and −3) and three initial rotation velocities (i.e., 0, 150, and 300 km s−1).
M. Limongi, A. Chieffi
semanticscholar   +1 more source

Kinetics of the tautomerization of thioimidic acids R−C(SH)NH → R−C(S)NH2: For R = H, F, HO, CN, NC, H2N, HC(O), HC(S), HC≡ C, CH3, CF3, H2C=CH, HOCH2, H2NCH2,CH3C(O), C2H5, (CH3)2CH, C6H5

International Journal of Chemical Kinetics, Volume 55, Issue 11, Page 731-742, November 2023., 2023
Abstract The kinetics of the tautomerization of thio‐imidic acids RC(SH)NH were determined at low (50–300 K) and high (500–1500 K) temperatures as R was varied to encompass mono‐ and diatomic species H, F, HO, NC, CN through H2N, HC(O), HC(S), HC≡ C, H3C, F3C, HOCH2, H2C=CH, CH3C(O), H2NCH2 and including ethyl, isopropyl and phenyl groups. The presence
Judith Würmel, John M. Simmie
wiley   +1 more source

Insights into AGB Nucleosynthesis Thanks to Spectroscopic Abundance Measurements in Intrinsic and Extrinsic Stars

Universe, 2022
The foundations of stellar nucleosynthesis have been established more than 70 years ago. Since then, much progress has been made, both on the theoretical side, with stellar evolution and nucleosynthesis models of increasing complexity, using more and ...
Sophie Van Eck, Shreeya Shetye, Lionel Siess   +2 more
doaj   +1 more source

Updating constraints on f(T) teleparallel cosmology and the consistency with big bang nucleosynthesis [PDF]

, 2020
We focus on viable f(T) teleparallel cosmological models, namely power law, exponential and square-root exponential, carrying out a detailed study of their evolution at all scales.
M. Benetti, S. Capozziello, G. Lambiase
semanticscholar   +1 more source

Ar+ ArH+ Reactive Collisions of Astrophysical Interest: The Case of 36Ar

ChemPhysChem, Volume 24, Issue 20, October 17, 2023., 2023
A complete theoretical investigation of the 36Ar+36ArH+ reactive collision involving the most abundant Argon isotope in the interstellar medium. Abstract The reactive collision between 36Ar and the 36ArH+ species has been investigated by means of quantum mechanical (QM), quasiclassical trajectories (QCT) and statistical quantum mechanical (SQM ...
María Judit Montes de Oca‐Estévez, Beatriz Darna, Borja García‐Ruiz, Rita Prosmiti, Tomás González‐Lezana, Debasish Koner   +5 more
wiley   +1 more source

Inhomogeneous Big-Bang Nucleosynthesis in Light of Recent Observations [PDF]

, 1998
We consider inhomogeneous big bang nucleosynthesis in light of the present observational situation. Different observations of He-4 and D disagree with each other, and depending on which set of observations one uses, the estimated primordial He-4 ...
Kainulainen, K., Kurki-Suonio, H., Sihvola, E.   +2 more
core   +2 more sources

Núcleos exóticos e síntese dos elementos químicos

Química Nova, 2012
We have around ninety chemical elements available in nature, which were produced mainly by nuclear reactions inside stars. The fusion reactions are the main synthesis process which generates the light and intermediate masses elements.
Nilton Teruya, Sérgio Barbosa Duarte
doaj   +1 more source

Mixing Uncertainties in Low-Metallicity AGB Stars: The Impact on Stellar Structure and Nucleosynthesis

Universe, 2021
The slow neutron-capture process (s-process) efficiency in low-mass AGB stars (1.5 < M/M⊙ < 3) critically depends on how mixing processes in stellar interiors are handled, which is still affected by considerable uncertainties.
Umberto Battino, Claudia Lederer-Woods, Borbála Cseh, Pavel Denissenkov, Falk Herwig   +4 more
doaj   +1 more source

Ab Initio Thermodynamics Calculation of Beta Decay Rates

Annalen der Physik, Volume 535, Issue 10, October 2023., 2023
Beta‐decay half‐lives are calculated ab initio from thermodynamics, independently of any quantum mechanics. The calculated values are close to those experimentally observed. Abstract Beta‐decay half‐lives for the free neutron, for 6He and 8He, and for 8Li are calculated ab initio from geometrical thermodynamics arguments, independently of any quantum ...
Michael C. Parker, Christopher Jeynes
wiley   +1 more source

Cosmological and astrophysical bounds on a heavy sterile neutrino and the KARMEN anomaly [PDF]

, 2000
Constraints on the lifetime of the heavy sterile neutrino, that was proposed as a possible interpretation of the KARMEN anomaly, are derived from primordial nucleosynthesis and SN 1987A.
A.D. Dolgov, Ahluwalia, Armbruster, Barbieri, Barger, Bilger, Burrows, Choudhury, Choudhury, D.V. Semikoz, Daum, Dolgov, Dolgov, Dolgov, Eitel, Enqvist, Enqvist, G. Raffelt, Gninenko, Goldman, Govaerts, Kachelrieß, Kainulainen, Kawano, Keil, Nötzold, Raffelt, Raffelt, Raffelt, S.H. Hansen, Tytler   +30 more
core   +2 more sources