相关论文: The Origin, Composition, and Energy Source for the…
Regardless of their close proximity, abundance measurements for both stars in {\alpha} Centauri by different groups have led to varying results. We have chosen to combine the abundance ratios from five similar data sets in order to reduce…
This article relates two topics of central importance in modern astronomy - the discovery some fifteen years ago of the first planets around other stars (exoplanets), and the centuries-old problem of understanding the origin of our own…
The first stars in the Universe are predicted to have been much more massive than the Sun. Gravitational condensation accompanied by cooling of the primordial gas due to molecular hydrogen, yields a minimum fragmentation scale of a few…
We examine electron-capture supernovae (ECSNe) as sources of elements heavier than iron in the solar system and in Galactic halo stars. Nucleosynthesis calculations are performed on the basis of thermodynamic histories of mass elements from…
In this chapter we review the astrophysical origins of Earth's carbon, starting from the products of the Big Bang and culminating with the Earth's formation. We review the measured compositions of different primitive objects including…
The elemental abundances of neon isotopes provide valuable insights into stellar evolution and nucleosynthesis. In this study, we calculate the abundances of the isotopes 18Ne, 19Ne, 20Ne, 21Ne, and 22Ne across the five principal…
The presence or absence of variations in the mass-independent abundances of Si isotopes in bulk meteorites provides important clues concerning the evolution of the early solar system. No Si isotopic anomalies have been found within the…
Cowan et al. (2021) review how roughly half the elements heavier than iron found in the Sun are produced by rapid neutron capture and half by slow neutron capture, the r- and s-processes. In the Sun, their relative contribution to…
The origin of the iron-group elements titanium to zinc in nature is understood to occur under explosive burning conditions in both Type Ia (thermonuclear) and Type II (core collapse) supernovae. In these dynamic environments, the most…
Observations of comets and asteroids show that the Solar Nebula that spawned our planetary system was rich in water and organic molecules. Bombardment brought these organics to the young Earth's surface, seeding its early chemistry. Unlike…
The presence and abundance of short lived radioisotopes (SLRs) $^{26}$Al and $^{60}$Fe in chondritic meteorites implies that the Sun formed in the vicinity of one or more massive stars that exploded as supernovae (SNe). Massive stars are…
Short-lived radioactive isotopes (SLRs) with half-lives between 0.1 to 100 Myr can be used to probe the origin of the Solar System. In this work, we examine the core-collapse supernovae production of the 15 SLRs produced: $^{26}$Al,…
Even if it tends to hide more often in the current autumnal season, our host star, the Sun, is the principal source of energy on our planet. It has a luminosity of 3.828e26 Watts, and despite that we receive only 2 parts per billion of…
Our Solar System originated in interstellar gas and dust; the latter is in the form of amorphous silicate particles and carbonaceous dust. The composition of cometary material shows that a significant fraction of the amorphous silicates was…
Element settling inside the Sun now becomes detectable from the comparison of the observed oscillation modes with the results of the theoretical models. This settling is due, not only to gravitation, but also to thermal diffusion and…
Recent studies have shown that the elemental abundances in the Sun are anomalous when compared to most (about 85%) nearby solar twin stars. Compared to its twins, the Sun exhibits a deficiency of refractory elements (those with condensation…
Theoretical physical-chemical models for the formation of planetary systems depend on data quality for the Sun's composition, that of stars in the solar neighbourhood, and of the estimated "pristine" compositions for stellar systems. The…
Representative abundances of the chemical elements for use as a solar abundance standard in astronomical and planetary studies are summarized. Updated abundance tables for solar system abundances based on meteorites and photospheric…
An overview of the sources for heavy elements in the early Galaxy is given. It is shown that observations of abundances in metal-poor stars can be used along with a basic understanding of stellar models to guide the search for the source of…
Helioseismology has shown that the chemical composition of the Sun has changed over its lifetime. The surface abundance of helium and heavy elements is believed to have decreased by up to 10% relative to their initial values. However, this…