- ID:
- ivo://CDS.VizieR/J/A+A/508/L17
- Title:
- Abundances in solar analogs
- Short Name:
- J/A+A/508/L17
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We derive the abundance of 19 elements in a sample of 64 stars with fundamental parameters very similar to solar, which minimizes the impact of systematic errors in our spectroscopic 1D-LTE differential analysis, using high-resolution (R~60000), high signal-to-noise ratio (S/N~200) spectra. The estimated errors in the elemental abundances relative to solar are as small as ~0.025dex. The abundance ratios [X/Fe] as a function of [Fe/H] agree closely with previously established patterns of Galactic thin-disk chemical evolution.
« Previous |
1 - 10 of 367
|
Next »
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/AZh/88/750
- Title:
- Abundances in stars of galactic sub-structures
- Short Name:
- J/AZh/88/750
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have determined abundances of copper, zinc, sodium, and aluminium in the atmospheres of 172 F, G, and K dwarf stars (-1.0<[Fe/H]<0.3) belonging to the Galaxy's thin and thick disks and to the Hercules moving group. Our observations were performed with the ELODIE echelle spectrometer on the 1.93-m telescope of the Haute ProvenceObservatory, with a resolving power of R=42000 and signal-to-noise ratio S/N>100. The Na, Al, Cu, and Zn abundances were derived in an LTE approximation; the synthetic spectrum for the copper lines was calculated taking into account super-fine structure of the lines. We analyzed the abundances of these elements as a function of metallicity [Fe/H] for stars of the thin and thick disks of the Galaxy and the Hercules moving group. The Cu abundances and their trends with metallicity are essentially the same in the three studied sub-structures. The mean Al and Zn abundances for stars of the thin and thick disks differ significantly.
- ID:
- ivo://CDS.VizieR/J/AJ/133/694
- Title:
- Abundances in the HR 1614 moving group
- Short Name:
- J/AJ/133/694
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present abundances for a sample of F, G, and K dwarfs of the HR 1614 moving group based on high-resolution, high signal-to-noise ratio spectra from the Anglo-Australian Telescope UCLES instrument. Our sample includes stars from Feltzing and Holmberg, as well as from Eggen. Abundances were derived for Na, Mg, Al, Si, Ca, Mn, Fe, Ni, Zr, Ba, Ce, Nd, and Eu.
- ID:
- ivo://CDS.VizieR/J/AJ/153/21
- Title:
- Abundances in the local region. II. F, G, and K dwarfs
- Short Name:
- J/AJ/153/21
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Parameters and abundances have been derived for 1002 stars of spectral types F, G, and K, and luminosity classes IV and V. After culling the sample for rotational velocity and effective temperature, 867 stars remain for discussion. Twenty-eight elements are considered in the analysis. The {alpha}, iron-peak, and Period 5 transition metal abundances for these stars show a modest enhancement over solar averaging about 0.05dex. The lanthanides are more abundant, averaging about +0.2dex over solar. The question is: Are these stars enhanced, or is the Sun somewhat metal-poor relative to these stars? The consistency of the abundances derived here supports an argument for the latter view. Lithium, carbon, and oxygen abundances have been derived. The stars show the usual lithium astration as a function of mass/temperature. There are more than 100 planet-hosts in the sample, and there is no discernible difference in their lithium content, relative to the remaining stars. The carbon and oxygen abundances show the well-known trend of decreasing [x/Fe] ratio with increasing [Fe/H].
- ID:
- ivo://CDS.VizieR/J/AJ/155/111
- Title:
- Abundances in the local region. III. Southern dwarfs
- Short Name:
- J/AJ/155/111
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Stellar parameters and abundances have been derived from a sample of 907 F, G, and K dwarfs. The high-resolution, high signal-to-noise spectra utilized were acquired with the HARPS spectrograph of the European Southern Observatory. The stars in the sample with -0.2<[Fe/H]<+0.2 have abundances that strongly resemble that of the Sun, except for the lithium content and the lanthanides. Near the solar temperature, stars show two orders of magnitude range in lithium content. The average content of stars in the local region appears to be enhanced at about the +0.1 level relative to the Sun for the lanthanides. There are over 100 planet hosts in this sample, and there is no discernible difference between them and the non-hosts regarding their lithium content.
- ID:
- ivo://CDS.VizieR/J/A+A/515/A28
- Title:
- Abundances of dwarfs and giants in 2 open clusters
- Short Name:
- J/A+A/515/A28
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- It has been suggested that the classical chemical analysis may be affected by systematic errors that would introduce abundance differences between dwarfs and giants. For some elements, the abundance difference could be real. We address the issue by observing 2 solar-type dwarfs in NGC 5822 and 3 in IC 4756, and comparing their composition with that of 3 giants in either of the aforementioned clusters. We determine iron abundance and stellar parameters for dwarf stars. Then, abundances of calcium, sodium, nickel, titanium, aluminium, chromium, and silicon were determined for both giants and dwarfs. The standard equivalent width analysis was performed differentially with respect to the Sun. We find an iron abundance for dwarf stars equal to solar to within the margins of error for IC 4756, and slightly above for NGC 5822 ([Fe/H]=0.01 and 0.05dex respectively). We show that, for sodium, silicon, and titanium, abundances of giants are significantly higher than those of the dwarfs of the same cluster (about 0.15, 0.15, and 0.35dex). Other elements may also undergo some enhanced, but all within 0.1dex.
- ID:
- ivo://CDS.VizieR/J/ApJ/878/99
- Title:
- Abundances of dwarfs & giants in NGC752 with HIRES
- Short Name:
- J/ApJ/878/99
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The chemical composition of stars in open clusters provides the best information on the chemical evolution of stars via comparison of main-sequence stars with evolved giants. This is a case study of the abundances in the dwarfs and giants in the old open cluster NGC 752. It is also a pilot program for automated abundance determinations, including equivalent-width measurements, stellar parameter determinations, and abundance analysis. We have found abundances of 31 element-ion combinations in 23 dwarfs and six giants. The mean cluster abundance of Fe is solar with [Fe/H]=-0.01+/-0.06 with no significant difference between the dwarfs and giants. We find that the cluster abundances of other elements, including alpha-elements, to be at or slightly above solar levels. We find some evidence for CNO processing in the spectra of the giants. The enhancement of Na in giants indicates that the NeNa cycle has occurred. The abundances of Mg and Al are similar in the dwarfs and giants, indicating that the hotter MgAl cycle has not occurred. We find no evidence of s-process enhancements in the abundances of heavy elements in the giants.
- ID:
- ivo://CDS.VizieR/J/A+A/552/A6
- Title:
- Abundances of F-G main-sequence stars
- Short Name:
- J/A+A/552/A6
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Detailed chemical abundances of volatile and refractory elements have been discussed in the context of terrestrial-planet formation during in past years. The HARPS-GTO high-precision planet-search program has provided an extensive database of stellar spectra, which we have inspected in order to select the best-quality spectra available for late type stars. We study the volatile-to-refractory abundance ratios to investigate their possible relation with the low-mass planetary formation.
- ID:
- ivo://CDS.VizieR/J/AJ/131/431
- Title:
- Abundances of Galactic G dwarfs
- Short Name:
- J/AJ/131/431
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have studied 23 long-lived G dwarfs that belong to the thin disk and thick disk stellar populations. The stellar data and analyses are identical, reducing the chances for systematic errors in the comparisons of the chemical abundance patterns in the two populations. Abundances have been derived for 24 elements: O, Na, Mg, Al, Si, Ca, Ti, Sc, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Y, Zr, Ba, La, Ce, Nd, and Eu.
- ID:
- ivo://CDS.VizieR/III/27A
- Title:
- Abundances of late G/K dwarfs in solar neighborhood
- Short Name:
- III/27A
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this investigation, a technique developed by Spinrad and Taylor for obtaining metal abundances of late-type stars, and used by them in an earlier investigation of evolved stars (see Cat. II/47), is applied to field dwarfs in the solar vicinity and to the Hyades. The colors determined from photoelectric spectrum-scanner observations are listed in the "raw_data.dat" file; the derived blocking factors are given in the "blocking.dat" file. These results were published as the Table 5 of the paper.
