相关论文: Fluorine Evolution in the Galactic Halo

We present the abundances of Li, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Co, Ni, Zn, Sr, Y, Zr, and Ba in a wide metallicity range ($-2.8 \le$ [Fe/H] $\le -1.5$). Using the differential technique allowed us to obtain an unprecedented low…

The evolution of the content of heavy elements in galaxies, the relative chemical abundances, their spatial distribution, and how these scale with various galactic properties, provide unique information on the galactic evolutionary…

Our knowledge about the chemical evolution of the more luminous dwarf spheroidal (dSph) galaxies is constantly growing. However, little is known about the enrichment of the ultrafaint systems recently discovered in large numbers in large…

The Bulge is the least understood major stellar population of the Milky Way. Most of what we know about the formation and evolution of the Bulge comes from bright giant stars. The underlying assumption that giants represent all the stars,…

Inhomogeneous chemical evolution models of galaxies which try to reproduce the scatter seen in element-to-iron ratios of metal-poor halo stars are heavily dependent on theoretical nucleosynthesis yields of core-collapse supernovae. Hence…

We present a theoretical investigation of the chemistry of fluorine-bearing molecules in diffuse and dense interstellar gas clouds. The chemistry of interstellar fluorine is qualitatively different from that of any other element, because -…

Revised spectroscopic parameters for the HF molecule and a new CN line list in the 2.3 mu region have been recently available, allowing a revision of the F content in AGB stars. AGB carbon stars are the only observationally confirmed…

Neutral fluorine (F I) lines are identified in the optical spectra of cool EHe stars. These are the first identification of F I lines in a star's spectrum, and provide the first measurement of fluorine abundances in EHe stars. The results…

Detailed elemental-abundance patterns of giant stars in the Galactic halo measured by APOGEE-2 have revealed the existence of a unique and significant stellar sub-population of silicon-enhanced ([Si/Fe]$\gtrsim +0.5$) metal-poor stars,…

The chemical evolution of galaxies is investigated within the framework of the star formation rate (SFR) dependent integrated galactic initial mass function (IGIMF). We study how the global chemical evolution of a galaxy and in particular…

We investigate the chemical evolution of odd-numbered elements such as sodium (Na) and aluminum (Al) during the early epochs of the Galactic halo with the use of a model that reproduces the observed box-shaped distribution of extremely…

The chemical abundances measured in stars of the Galactic bulge offer an unique opportunity to test galaxy formation models as well as impose strong constraints on the history of star formation and stellar nucleosynthesis. The aims of this…

New information on the relations between the Galactic disks, the halo, and satellite galaxies is being obtained from elemental abundances of stars having metallicities in the range -1.5 < [Fe/H] < -0.5. The first results for a sample of 26…

The main objective of this paper is to explore abundances of fluorine in hot Extreme Helium Stars (EHes). Overabundance of fluorine is a characteristic feature for cool EHes and R Coronae Borealis (RCB) stars and further enforces their…

We compute the evolution of different abundance ratios in the Milky Way (MW) for two different sets of stellar yields. In one of them stellar rotation is taken into account and we investigate its effects on the chemical evolution model…

Galactic bulges are central to understanding galaxy formation and evolution. Here we report on recent studies using micro-lensing events to obtain spectra of high resolution and moderately high signal-to-noise ratios of dwarf stars in the…

Recent studies show that the chemical evolution of Sr and Ba in the Galaxy can be explained if different production sites, hosting r- and s-processes, are taken into account. However, the question of unambiguously identifying these sites is…

We have found the fluorine lines [F IV] 3996.92A,4059.90A in the extremely metal-poor ([Ar/H] = -2.10+/-0.21) halo planetary nebula (PN) BoBn 1 in high-dispersion spectra from the 8.2-m VLT/UVES archive. Chemical abundance analysis shows…

In this study, we investigate the distribution and origin of chemical elements in different stellar components of simulated Milky Way-like galaxies in relation to their mass assembly history, stellar age, and metallicity. Using a sample of…

We measured $^{35}$Cl abundances in 52 M giants with metallicities between -0.5 $<$ [Fe/H] $<$ 0.12. Abundances and atmospheric parameters were derived using infrared spectra from CSHELL on the IRTF and from optical echelle spectra. We…