Related papers: Metallic species in interstellar medium: Astrochem…
Abundances of five elements, Na, Mg, Al, Si, and Sr, are investigated for 44 very metal-poor stars (-4.0 < [Fe/H] < -1.5) in the Galactic halo system based on an Local Thermodinamic Equilibrium (LTE) analysis of high-resolution…
We present a census of the mass density of metals and their evolution with cosmic time on a global scale throughout the Universe, synthesizing robust estimates of metals in stars, hot intra-cluster gas, and gaseous absorbers tracing neutral…
Metallicity is a fundamental parameter that contributes to the physical characteristics of a star. However, the low temperatures and complex molecules present in M dwarf atmospheres make it difficult to measure their metallicities using…
The O/H metallicity distribution of different samples of planetary nebulae in the bulge of the Milky Way and M31 are compared. O/H abundances are converted into [Fe/H] metallicity by the use of theoretical [O/Fe] x [Fe/H] relationships both…
We have examined the metal enrichment of the intergalactic medium (IGM) based on a galactic wind model. A galactic wind driven by supernovae brings metallic gas to the IGM but not so far beyond the gravitational potential. The expanding…
Large numbers of low-to-medium resolution spectra of M-type dwarf stars from both the local Galactic disk and halo are available from various surveys. In order to fully exploit these data, we develop a template-fit method using a set of…
Context: Diffusion of species on the dust surface is a key process for determining the chemical composition of interstellar ices. On the dust surface, adsorbed species diffuse from one potential well to another and react with other adsorbed…
We performed spectral analysis of Suzaku data of the galactic disk and outflow regions of the starburst galaxy M82. Thermal modeling of the central disk regions requires at least three temperature components. The Ly$\beta$ line fluxes of O…
We present K band spectra for 133 nearby (d < 33 parsecs) M dwarfs, including 18 M dwarfs with reliable metallicity estimates (as inferred from an FGK type companion), 11 M dwarf planet hosts, more than 2/3 of the M dwarfs in the Northern 8…
There are different environments in the interstellar medium (ISM), depending on the density, temperature and chemical composition. Among them, molecular clouds, often referred to as the cradle of stars, are paradigmatic environments…
In previous works, we computed abundances for the red giant in nearly four dozen S-type symbiotic systems (SySt). The abundances provide information about metallicity, evolutionary status, and possible memberships in Galactic stellar…
Nuclear inflows of metal-poor interstellar gas triggered by galaxy interactions can account for the systematically lower central oxygen abundances observed in local interacting galaxies. Here, we investigate the metallicity evolution of a…
Context. Carbon monoxide (CO) is arguably the most important molecule for interstellar organic chemistry. Its binding to amorphous solid water (ASW) ice regulates both diffusion and desorption processes. Accurately characterizing the CO…
The Damped and sub-Damped Lyman-alpha (DLA and sub-DLA) systems seen in the spectra of QSOs offer a unique way to study the interstellar medium of high redshift galaxies. In this paper we report on new abundance determinations in a sample…
Laboratory experiments are essential in exploring the mechanisms involved in stardust formation. One key question is how a metal is incorporated into dust for an environment rich in elements involved in stardust formation (C, H, O, Si). To…
Stellar parameters of 25 planet-hosting stars and abundances of Li, C, O, Na, Mg, Al, S, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Ni, Zn, Y, Zr, Ba, Ce, Pr, Nd, Sm and Eu, were studied based on homogeneous high resolution spectra and uniform…
We develop a simple analytical model that tracks galactic metallicities governed by star formation and feedback to gain insight from the observed galaxy stellar mass-metallicity relations over a large range of stellar masses and redshifts.…
The cycling of metals between interstellar gas and dust is a critical aspect of the baryon cycle of galaxies, yet our understanding of this process is limited. This study focuses on understanding dust depletion effects in the low…
Many chemical models of dense interstellar clouds predict that the majority of gas-phase elemental nitrogen should be present as N2, with an abundance approximately five orders of magnitude less than that of hydrogen. As a homonuclear…
We report the abundances of 30 elements in 23 metal-poor ([Fe/H] <-1.7) giants. These are based on 7774 equivalent widths and spectral synthesis of 229 additional lines. Hyperfine splitting is taken into account when appropriate. Our choice…