Search

Start Over Validation Level 2 Capability Type Simple Cone Search
211. Abundances of M33 HII regions
ID:
ivo://CDS.VizieR/J/A+A/512/A63
Title:
Abundances of M33 HII regions
Short Name:
J/A+A/512/A63
Date:
21 Oct 2021
Publisher:
CDS
Description:
We analyze the spatial distribution of metals in M33 using a new sample and literature data of HII regions, constraining a model of galactic chemical evolution with HII region and planetary nebula (PN) abundances. We consider chemical abundances of a new sample of HII regions complemented with previous literature data-sets. Supported by a uniform sample of nebular spectroscopic observations, we conclude that: i) the metallicity distribution in M33 is very complex, showing a central depression in metallicity probably due to observational bias; ii) the metallicity gradient in the disk of M33 has a slope of -0.037+/-0.009dex/kpc in the whole radial range up to ~8kpc, and -0.044+/-0.009dex/kpc excluding the central kpc; iii) there is a small evolution of the slope with time from the epoch of PN progenitor formation to the present-time. Description: Emission line fluxes, observed and dereddened of 33 HII regions are presented. Physical and chemical properties, such as electron temperatures and density, ionic and total chemical abundances of He, O, N, Ne, Ar, S, are derived.
212. Abundances of microlensed bulge dwarf stars. V.
ID:
ivo://CDS.VizieR/J/A+A/549/A147
Title:
Abundances of microlensed bulge dwarf stars. V.
Short Name:
J/A+A/549/A147
Date:
21 Oct 2021
Publisher:
CDS
Description:
We perform a detailed elemental abundance analysis of dwarf stars in the Galactic bulge, based on high-resolution spectra that were obtained while the stars were optically magnified during gravitational microlensing events. The analysis method is the same as for a large sample of F and G dwarf stars in the Solar neighbourhood, enabling a fully differential comparison between the Bulge and the local stellar populations in the Galactic disc.
213. Abundances of microlensed Bulge dwarf stars. VI.
ID:
ivo://CDS.VizieR/J/A+A/605/A89
Title:
Abundances of microlensed Bulge dwarf stars. VI.
Short Name:
J/A+A/605/A89
Date:
21 Oct 2021
Publisher:
CDS
Description:
We perform a detailed elemental abundance analysis of dwarf stars in the Galactic bulge, based on high-resolution spectra that were obtained while the stars were optically magnified during gravitational microlensing events. The analysis method is the same as for a large sample of F and G dwarf stars in the Solar neighbourhood, enabling a fully differential comparison between the Bulge and the local stellar populations in the Galactic disc.
214. Abundances of microlensed stars in the Bulge
ID:
ivo://CDS.VizieR/J/A+A/533/A134
Title:
Abundances of microlensed stars in the Bulge
Short Name:
J/A+A/533/A134
Date:
21 Oct 2021
Publisher:
CDS
Description:
We perform a detailed elemental abundance analysis of dwarf stars in the Galactic bulge, based on high-resolution spectra that were obtained while the stars were optically magnified during gravitational microlensing events. The analysis method is the same as for a large sample of F and G dwarf stars in the Solar neighbourhood, enabling a fully differential comparison between the Bulge and the local stellar populations in the Galactic disc.
215. Abundances of microlensed stars in the Bulge
ID:
ivo://CDS.VizieR/J/A+A/512/A41
Title:
Abundances of microlensed stars in the Bulge
Short Name:
J/A+A/512/A41
Date:
21 Oct 2021
Publisher:
CDS
Description:
We perform a detailed elemental abundance analysis of dwarf stars in the Galactic bulge, based on high-resolution spectra that were obtained while the stars were optically magnified during gravitational microlensing events. The analysis method is the same as for a large sample of F and G dwarf stars in the Solar neighbourhood, enabling a fully differential comparison between the Bulge and the local stellar populations in the Galactic disc.
216. Abundances of M22 subgiants
ID:
ivo://CDS.VizieR/J/A+A/541/A15
Title:
Abundances of M22 subgiants
Short Name:
J/A+A/541/A15
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present an abundance analysis of 101 subgiant branch (SGB) stars in the globular cluster M22. Using low-resolution FLAMES/GIRAFFE spectra we have determined abundances of the neutron-capture strontium and barium and the light element carbon. With these data we explore relationships between the observed SGB photometric split in this cluster and two stellar groups characterized by different contents of iron, slow neutron-capture process (s-process) elements, and the {alpha} element calcium, which we previously discovered in M22's red-giant stars.
217. Abundances of nearby late-type galaxies. I. Data
ID:
ivo://CDS.VizieR/J/AJ/147/131
Title:
Abundances of nearby late-type galaxies. I. Data
Short Name:
J/AJ/147/131
Date:
21 Oct 2021
Publisher:
CDS
Description:
We investigate the oxygen and nitrogen abundance distributions across the optical disks of 130 nearby late-type galaxies using around 3740 published spectra of HII regions. We use these data in order to provide homogeneous abundance determinations for all objects in the sample, including HII regions in which not all of the usual diagnostic lines were measured. Examining the relation between N and O abundances in these galaxies we find that the abundances in their centers and at their isophotal R_25_ disk radii follow the same relation. The variation in N/H at a given O/H is around 0.3dex. We suggest that the observed spread in N/H may be partly caused by the time delay between N and O enrichment and the different star formation histories in galaxies of different morphological types and dimensions. We study the correlations between the abundance properties (central O and N abundances, radial O and N gradients) of a galaxy and its morphological type and dimension.
218. Abundances of nearby red clump giants
ID:
ivo://CDS.VizieR/J/MNRAS/382/553
Title:
Abundances of nearby red clump giants
Short Name:
J/MNRAS/382/553
Date:
21 Oct 2021
Publisher:
CDS
Description:
Based on the analysis of high-resolution spectra with a high signal-to-noise ratio, we have determined the abundances of the alpha-elements O, Si, Ca and Ti, the iron peak elements V, Fe and Ni, and the heavy element Ba without the consideration of non-local thermodynamic equilibrium (NLTE) effect and the light neutron-rich elements Na, Mg and Al with an NLTE analysis for 63 nearby red clump giants. Fe abundances cover a logarithmic range between 0.60 and +0.35 relative to solar. All abundance ratios with respect to Fe are similar to those found in the Sun. Hyperfine structure (HFS) was taken into account when calculating V lines. The difference in abundances obtained with and without HFS can be as large as 0.5 dex.
219. Abundances of neutron-capture elements
ID:
ivo://CDS.VizieR/J/A+A/649/A126
Title:
Abundances of neutron-capture elements
Short Name:
J/A+A/649/A126
Date:
22 Feb 2022
Publisher:
CDS
Description:
The aim of this work is to determine abundances of neutron-capture elements for thin- and thick-disc F, G, and K stars in several selected sky fields near the North Ecliptic Pole and to compare the results with the Galactic chemical evolution models, to explore elemental gradients according to stellar ages, mean galactocentric distances, and maximum heights above the Galactic plane. The observational data were obtained with the 1.65 meter telescope at the Moletai Astronomical Observatory and a fibre-fed high-resolution spectrograph covering a full visible wavelength range (4000-8500{AA}). Elemental abundances were determined using a differential line-by-line spectrum synthesis using the TURBOSPECTRUM code with the MARCS stellar model atmospheres and accounting for the hyperfine-structure effects. Results. We determined abundances of Sr, Y, Zr, Ba, La, Ce, Pr, Nd, Sm, and Eu for 424 thin- and 82 thick-disc stars. The sample of thick-disc stars shows a clearly visible decrease of [Eu/Mg] with increasing metallicity compared to the thin-disc stars, bringing more evidences of different chemical evolution in these two Galactic components. Abundance correlation with age slopes for the investigated thin-disc stars are slightly negative for the majority of s-process dominated elements, while r-process dominated elements have positive correlations. Our sample of thin-disc stars with ages spanning from 0.1 to 9Gyrs gives the [Y/Mg]=0.022(+/-0.015)-0.027(+/-0.003)/age[Gyr] relation. However, for the thick-disc stars, when taking into account also data from other studies, we found that [Y/Mg] cannot serve as an age indicator. The radial abundance-to-iron gradients in the thin disc are negligible for the s-process dominated elements and become positive for the r-process dominated elements, the vertical gradients are negative for the light s-process dominated elements and become positive for the r-process dominated elements. In the thick disc, the radial abundance-to-iron slopes are negligible and the vertical ones are predominantly negative.
220. Abundances of 7 new member stars in Tucana II
ID:
ivo://CDS.VizieR/J/ApJ/857/74
Title:
Abundances of 7 new member stars in Tucana II
Short Name:
J/ApJ/857/74
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present chemical abundance measurements for seven stars with metallicities ranging from [Fe/H]=-3.3 to [Fe/H]=-2.4 in the TucanaII ultra-faint dwarf galaxy (UFD), based on high-resolution spectra obtained with the MIKE spectrograph on the 6.5m Magellan-Clay Telescope. For three stars, we present detailed chemical abundances for the first time. Of those, two stars are newly discovered members of Tucana II and were selected as probable members from deep narrowband photometry of the Tucana II UFD taken with the SkyMapper telescope. This result demonstrates the potential for photometrically identifying members of dwarf galaxy systems based on chemical composition. One new star was selected from the membership catalog of Walker+ (2016, J/ApJ/819/53). The other four stars in our sample have been reanalyzed, following additional observations. Overall, six stars have chemical abundances that are characteristic of the UFD stellar population. The seventh star shows chemical abundances that are discrepant from the other Tucana II members and an atypical, higher strontium abundance than what is expected for typical UFD stars. While unlikely, its strontium abundance raises the possibility that it may be a foreground metal-poor halo star with the same systemic velocity as Tucana II. If we were to exclude this star, Tucana II would satisfy the criteria to be a surviving first galaxy. Otherwise, this star implies that Tucana II has likely experienced somewhat extended chemical evolution.

Limit your search

more »

more »

more »

more »

more »

more »