- ID:
- ivo://CDS.VizieR/J/AJ/129/303
- Title:
- Abundances of stars in M3 and M13
- Short Name:
- J/AJ/129/303
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have carried out a detailed abundance analysis for 21 elements in a sample of 27 stars with a wide range in luminosity from luminous giants to stars near the main-sequence turnoff in the globular cluster M13 ([Fe/H]=-1.50dex) and in a sample of 13 stars distributed from the tip to the base of the red giant branch (RGB) in the globular cluster M3 ([Fe/H]=-1.39dex). The analyzed spectra, obtained with HIRES at the Keck Observatory, are of high dispersion (R={lambda}/{Delta}{lambda}=35000).
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/854/184
- Title:
- Abundances of stars in 3 open clusters
- Short Name:
- J/ApJ/854/184
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Single stars in open clusters with known distances are important targets in constraining the nucleosynthesis process since their ages and luminosities are also known. In this work, we analyze a sample of 29 single red giants of the open clusters NGC2360, NGC3680, and NGC5822 using high-resolution spectroscopy. We obtained atmospheric parameters, abundances of the elements C, N, O, Na, Mg, Al, Ca, Si, Ti, Ni, Cr, Y, Zr, La, Ce, and Nd, as well as radial and rotational velocities. We employed the local thermodynamic equilibrium atmospheric models of Kurucz and the spectral analysis code moog. Rotational velocities and light-element abundances were derived using spectral synthesis. Based on our analysis of the single red giants in these three open clusters, we could compare, for the first time, their abundance pattern with that of the binary stars of the same clusters previously studied. Our results show that the abundances of both single and binary stars of the open clusters NGC 2360, NGC 3680, and NGC 5822 do not have significant differences. For the elements created by the s-process, we observed that the open clusters NGC2360, NGC3680, and NGC5822 also follow the trend already raised in the literature that young clusters have higher s-process element abundances than older clusters. Finally, we observed that the three clusters of our sample exhibit a trend in the [Y/Mg]-age relation, which may indicate the ability of the [Y/Mg] ratio to be used as a clock for the giants.
- ID:
- ivo://CDS.VizieR/J/ApJ/701/1053
- Title:
- Abundances of 8 stars in the Draco dSph
- Short Name:
- J/ApJ/701/1053
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an abundance analysis based on high-resolution spectra of eight stars selected to span the full range in metallicity in the Draco dwarf spheroidal (dSph) galaxy. We find that [Fe/H] for the sample stars ranges from -1.5 to -3.0dex. Combining our sample with previously published work for a total of 14 luminous Draco giants, we show that the abundance ratios [Na/Fe], [Mg/Fe], and [Si/Fe] for the Draco giants overlap those of Galactic halo giants at the lowest [Fe/H] probed, but are significantly lower for the higher Fe-metallicity Draco stars. Using a toy model we compare the behavior of the abundance ratios within the sample of Draco giants with those from the literature of Galactic globular clusters, and the Carina and Sgr dSph galaxies.
- ID:
- ivo://CDS.VizieR/J/AJ/135/1551
- Title:
- Abundances of stars in 47 Tuc
- Short Name:
- J/AJ/135/1551
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present chemical abundances for O, Na, Mg, Al, Si, Ca, Ti, and Fe in eight red giants and one turnoff star in the metal-rich globular cluster 47 Tuc, based on spectroscopy with the Magellan Inamori Kyocera Echelle high-resolution spectrograph on the Magellan 6.5m Clay telescope. A robust line by a line differential abundance analysis technique, relative to the K-giant Arcturus, was used to reduce systematic errors from atmospheric and atomic parameters.
- ID:
- ivo://CDS.VizieR/J/AJ/129/1063
- Title:
- Abundances of stars within 15pc of the Sun
- Short Name:
- J/AJ/129/1063
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an abundance analysis for stars within 15pc of the Sun located north of -30{deg} declination. We have limited our abundance sample to absolute magnitudes brighter than +7.5 and have eliminated several A stars in the local vicinity. Our final analysis list numbers 114 stars. Unlike Allende Prieto et al. (2004, Cat. <J/A+A/420/183>) in their consideration of a very similar sample, we have enforced strict spectroscopic criteria in the determination of atmospheric parameters. Nevertheless, our results are very similar to theirs. We determine the mean metallicity of the local region to be <[Fe/H]>=-0.07 using all stars and -0.04 when interlopers from the thick disk are eliminated.
- ID:
- ivo://CDS.VizieR/J/ApJ/732/55
- Title:
- Abundances of stars with planets
- Short Name:
- J/ApJ/732/55
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Precise abundances of 18 elements have been derived for 10 stars known to host giant planets from high signal-to-noise ratio, high-resolution echelle spectroscopy. Internal uncertainties in the derived abundances are typically <~0.05dex. The stars in our sample have all been previously shown to have abundances that correlate with the condensation temperature (T_c_) of the elements in the sense of increasing abundances with increasing T_c_; these trends have been interpreted as evidence that the stars may have accreted H-depleted planetary material. Our newly derived abundances also correlate positively with T_c_, although slopes of linear least-square fits to the [m/H]-T_c_ relations for all but two stars are smaller here than in previous studies. When considering the refractory elements (T_c_>900K) only, which may be more sensitive to planet formation processes, the sample can be separated into a group with positive slopes (four stars) and a group with flat or negative slopes (six stars). The four stars with positive slopes have very close-in giant planets (three at 0.05AU) and slopes that fall above the general Galactic chemical evolution trend. We suggest that these stars have accreted refractory-rich planet material but not to the extent that would increase significantly the overall stellar metallicity. The flat or negative slopes of the remaining six stars are consistent with recent suggestions of a planet formation signature, although we show that the trends may be the result of Galactic chemical evolution.
- ID:
- ivo://CDS.VizieR/J/AJ/127/2723
- Title:
- Abundances of 3 supergiants in Sextans A
- Short Name:
- J/AJ/127/2723
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the abundance analyses of three isolated A-type supergiant stars in the dwarf irregular galaxy Sextans A (=DDO 75) from high-resolution spectra obtained with the Ultraviolet-Visual Echelle Spectrograph (UVES) on the Kueyen telescope (UT2) of the ESO Very Large Telescope (VLT). Detailed model atmosphere analyses have been used to determine the stellar atmospheric parameters and the elemental abundances of the stars.
- ID:
- ivo://CDS.VizieR/J/MNRAS/368/247
- Title:
- Abundances of 6 suspected CP stars
- Short Name:
- J/MNRAS/368/247
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The abundance pattern of six stars classified as suspected chemically peculiar in the General Catalogue of Ap and Am stars (<III/162>) by Renson has been derived to ascertain the real nature of these objects. Spectroscopic observations in the range {lambda}{lambda}4800-5600{AA} have been carried out at the stellar station of the INAF Catania Astrophysical Observatory. Among the studied stars, for only three of them we confirmed their peculiarity, HD 155102 being a silicon star, HD 159082 a mercury-manganese star and HD 162132 a moderate metallic A-type star. The other three objects have chemical abundances not so different from the standard values derived in the literature for A-type stars and, furthermore, they do not show light variability. Hence, we suggest that they could be ruled out from Renson's catalogue.
- ID:
- ivo://CDS.VizieR/J/ApJ/838/44
- Title:
- Abundances of the brightest member of Tuc III
- Short Name:
- J/ApJ/838/44
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Chemically peculiar stars in dwarf galaxies provide a window for exploring the birth environment of stars with varying chemical enrichment. We present a chemical abundance analysis of the brightest star in the newly discovered ultra-faint dwarf galaxy candidate TucanaIII. Because it is particularly bright for a star in an ultra-faint Milky Way (MW) satellite, we are able to measure the abundance of 28 elements, including 13 neutron-capture species. This star, DESJ235532.66-593114.9 (DES J235532), shows a mild enhancement in neutron-capture elements associated with the r-process and can be classified as an r-I star. DES J235532 is the first r-I star to be discovered in an ultra-faint satellite, and Tuc III is the second extremely low-luminosity system found to contain r-process enriched material, after Reticulum II. Comparison of the abundance pattern of DES J235532 with r-I and r-II stars found in other dwarf galaxies and in the MW halo suggests a common astrophysical origin for the neutron-capture elements seen in all r-process enhanced stars. We explore both internal and external scenarios for the r-process enrichment of Tuc III and show that with abundance patterns for additional stars, it should be possible to distinguish between them.
- ID:
- ivo://CDS.VizieR/J/AJ/144/35
- Title:
- Abundances of the eclipsing binary ZZ Boo
- Short Name:
- J/AJ/144/35
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigated ZZ Boo using a high-resolution (R=80000) spectrum obtained at the BOES echelle spectrograph attached to a 1.8m telescope at the Bohuynsan observatory in Korea. The atmospheric parameters of the components were found using the published photometrical observations and the abundance analysis of iron lines: the flux ratio of the components F_A_/F_B_=1.12+/-0.15, the effective temperatures of the components T_eff_=6860+/-20K and 6930+/-20K, the surface gravities log g=3.72+/-0.10 and 3.84+/-0.10, the metallicities [Fe/H]=-0.10+/-0.08 and -0.03+/-0.10, and the projected rotation velocities vsin i=11.9+/-0.4km/s and 19.3+/-0.8km/s for the primary and secondary components, respectively. The pointed errors are the formal errors of the methods used; the systematic errors of the temperatures, gravities, metallicities, and projected rotational velocities can be as high as 250-300K, 0.3dex, 0.15dex, and 4km/s, respectively. The abundances of 24 and 22 chemical elements were determined in the atmospheres of the components. The abundance pattern of the primary component shows the solar or slightly undersolar abundances of all elements. CNO abundances are close to solar values. The abundance pattern of this component resembles those of {lambda} Boo type stars. The abundances of light elements, except oxygen, in the atmosphere of the secondary component are practically solar. The abundances of barium and two detected lanthanides are close to the solar values; the overabundance of oxygen is 0.9dex. The abundances of two components are evidently different. The comparison of relative abundances with the condensation temperatures and second ionization potentials of the elements confirms the difference in abundance patterns and allows discussion of the different accretion scenarios for two components of this binary system.
