Results 11 to 20 of about 92 (70)
THE SPECTRAL EVOLUTION OF CONVECTIVE MIXING WHITE DWARFS, THE NON-DA GAP, AND WHITE DWARF COSMOCHRONOLOGY [PDF]
Astrophysical Journal Letters, 2012 Submitted to ApJL on Feb. 20, 2012.
Brad M S Hansen
exaly +4 more sources
Nuclear cosmochronology within analytic models of the chemical evolution of the solar neighbourhood [PDF]
Monthly Notices of the Royal Astronomical Society, 1988 This paper investigates whether the age of the Galaxy can be deduced from natural radioactivity. I demonstrate that two recent influential claims (by Butcher and by Fowler) that such observations set the age at TG = 10 Gyr depend on special assumptions that run counter to existing astrophysical theory, so that greater ages are possible.
D D Clayton, Clayton Donald D
exaly +2 more sources
Nuclear reactions in astrophysics
Eurasian Journal of Physics and Functional Materials, 2021 This work is an attempt to present some problems on the evolution of the Universe: the nucleosynthesis and cosmochronology from the standpoint of physics of particles and nuclei, in particular with the use of the lat est results, obtained by means of ...
Yu. E. Penionzhkevich
doaj +1 more source
The Astrophysical Journal Letters, 2023 We present a U-corrected Pb–Pb age of 4566.19 ± 0.20 Ma (1.11 ± 0.26 Myr after t _0 ) for the moderately volatile element rich, andesitic meteorite Erg Chech 002 (EC002). Our Al–Mg isochron defines a ^26 Al/ ^27 Al initial ratio of (8.65 ± 0.09) × 10 ^−6
J. N. Connelly +5 more
doaj +1 more source
The Planetary Science Journal, 2023 The history of accretion and differentiation processes in the planetesimals is provided by various groups of meteorites. Sampling different parent body layers, they reveal the circumstances of the metal–silicate segregation and the internal structures of
Wladimir Neumann +4 more
doaj +1 more source
The Q Branch Cooling Anomaly Can Be Explained by Mergers of White Dwarfs and Subgiant Stars
The Astrophysical Journal Letters, 2023 Gaia's exquisite parallax measurements allowed for the discovery and characterization of the Q branch in the Hertzsprung–Russell diagram, where massive C/O white dwarfs (WDs) pause their dimming due to energy released during crystallization ...
Ken J. Shen +2 more
doaj +1 more source
Uranium Abundances and Ages of r-process Enhanced Stars with Novel U ii Lines
The Astrophysical Journal, 2023 The ages of the oldest stars shed light on the birth, chemical enrichment, and chemical evolution of the universe. Nucleocosmochronometry provides an avenue to determining the ages of these stars independent from stellar-evolution models.
Shivani P. Shah +9 more
doaj +1 more source
PROTOGALACTIC MERGERS AND COSMOCHRONOLOGY
The Astrophysical Journal, 1993 We construct schematic models for chemical evolution and cosmochronology within the expanding and collapsing protogalactic halo followed by formation of the local disk. Star formation is associated with both the rate of protogalactic mergers and the intrinsic gas density of protogalactic clouds and the disk.
G. J. Mathews, D. N. Schramm
openaire +1 more source
Nucleosynthesis and Nucleo-Cosmochronology
EAS Publications Series, 2004 I discuss a few selected topics on nucleosynthesis and nucleo-cosmochronology in faint, if not totally illusory, hopes of helping to gain a clear perspective of the future astronuclear physics. First I illustrate a few puzzles that remain to be solved by observational astronomy, theoretical astrophysics, and some nuclear physics experiments so as to ...
Arnould, Marcel, Goriely, Stéphane
openaire +4 more sources
R‐Process Nucleosynthesis in MHD Jet Explosions of Core‐Collapse Supernovae
Journal of Astrophysics, Volume 2013, Issue 1, 2013., 2013 We investigate the r‐process nucleosynthesis during the magnetohydrodynamical (MHD) explosion of a supernova in a helium star of 3.3 M⊙, where effects of neutrinos are taken into account using the leakage scheme in the two‐dimensional (2D) hydrodynamic code.
Motoaki Saruwatari +6 more
wiley +1 more source