Related papers: The Chemical Evolution of Phosphorus

Phosphorus related species are not known to be as omnipresent in space as hydrogen, carbon, nitrogen, oxygen, and sulfur-bearing species. Astronomers spotted very few P-bearing molecules in the interstellar medium and circumstellar…

The chemical elements are created in nuclear fusion processes in the hot and dense cores of stars. The energy generated through nucleosynthesis allows stars to shine for billions of years. When these stars explode as massive supernovae, the…

We examine the Pb and Th abundances in 27 metal-poor stars (-3.1 < [Fe/H] < -1.4) whose very heavy metal (Z > 56) enrichment was produced only by the rapid (r-) nucleosynthesis process. New abundances are derived from HST/STIS, Keck/HIRES,…

Sulfur is one of the most abundant elements in the Universe, yet the sulfur budget inferred from the observed sulfur-bearing molecules in dense cores is significantly lower than expected. Starless and pre-stellar cores represent the…

Due to their production sites, as well as to how they are processed and destroyed in stars, the light elements are excellent tools to investigate a number of crucial issues in modern astrophysics: from stellar structure and non-standard…

Studying a range of old metal-poor stars provides information over cosmological timescales of our Galaxy. Such studies are indicative of the pristine gases and evolution of the Milky Way. Deriving stellar parameters and abundances from…

We report on the abundance analysis of two red giants in the faint Hercules dwarf spheroidal (dSph) galaxy. These stars show a remarkable deficiency in the neutron-capture elements, while the hydrostatic alpha-elements (O, Mg) are strongly…

We have performed a comprehensive chemical abundance analysis of the extremely metal-poor ([Ar/H]<-2) halo planetary nebula (PN) BoBn 1 based on IUE archive data, Subaru/HDS spectra, VLT/UVES archive data, and Spitzer/IRS spectra. We have…

I review a technique for interpreting faint galaxy data which traces the evolution with cosmic time of the galaxy luminosity density, as determined from several deep spectroscopic samples and the HDF. The method relies on the rest frame UV…

(Abridged) The abundances of alpha-elements are a powerful diagnostic of the star formation history and chemical evolution of a galaxy. Sulphur, being moderately volatile, can be reliably measured in the interstellar medium (ISM) of damped…

The light elements beryllium (Be; $Z=4$) and boron (B; $Z=5$) are mainly produced by spallation reactions between cosmic rays and carbon (C; $Z=6$), nitrogen (N; $Z=7$), and oxygen (O; $Z=8$) nuclei. Only traces of Be or B would have been…

We report the results of a coherent study of three chemically anomalous metal-poor ([Fe/H] ~ -2) stars. These objects exhibit unusually low abundances of Mg, Si, Ca (alpha-elements) and Sr, Y, and Ba (neutron-capture elements). Our analyses…

We present homogeneous abundance analysis of over 20 elements for 385 very metal-poor (VMP) stars based on the LAMOST survey and follow-up observations with the Subaru Telescope. It is the largest high-resolution VMP sample (including 363…

Palladium (Pd) and silver (Ag) are the key elements for probing the weak component in the rapid neutron-capture process (r-process) of stellar nucleosynthesis. We performed a detailed analysis of the high-resolution and high signal-to-noise…

The chemical evolution of fluorine is investigated in a sample of Milky Way red giantstars that span a significant range in metallicity from [Fe/H] $\sim$ -1.3 to 0.0 dex. Fluorine abundances are derived from vibration-rotation lines of HF…

A long sought after goal using chemical abundance patterns derived from metal-poor stars is to understand the Galactic chemical evolution (GCE) and to pin down the nature of the first stars (Pop III). Here, we use a sample of 14 metal-poor…

Abundances of about 18 elements including the heavy elements Y and Zr are determined from Hubble Space Telescope Space Telescope Imaging Spectrograph ultraviolet spectra of seven extreme helium stars (EHes): LSE 78, BD+10 2179, V1920 Cyg,…

We have used UVES on VLT-UT2 to take spectra of 15 individual red giant stars in the centers of four nearby dwarf spheroidal galaxies: Sculptor, Fornax, Carina and Leo I. We measure the abundance variations of numerous elements in these low…

We present a detailed chemical abundance analysis of HE 1300+0157, a subgiant with [Fe/H]=-3.9. From a high-resolution, high-S/N Subaru/HDS spectrum we find the star to be enriched in C ([C/Fe]_1D ~ +1.4) and O ([O/Fe]_1D ~ +1.8). With the…

We have analyzed high-resolution and high signal-to-noise ratio optical spectra of nearby FGK stars with and without detected giant planets in order to homogeneously measure their photospheric parameters, mass, age, and the abundances of…