- ID:
- ivo://CDS.VizieR/J/A+A/630/A149
- Title:
- Disk and halo stars C, O and Fe abundances (Amarsi+, 2019)
- Short Name:
- J/A+A/630/A149
- Date:
- 27 Sep 2019 05:42:26
- Publisher:
- CDS
- Description:
- Spectrum synthesis calculations were performed on four different families of model atmospheres: 3D hydrodynamic model atmospheres from the STAGGER-grid (Magic et al. 2013A&A...557A..26M, Cat. J/A+A/557/A26); 1D model atmospheres determined by averaging the <3D> STAGGER model atmospheres (henceforth <3D> model atmospheres; Magic et al. 2013A&A...560A...8M, Cat. J/A+A/560/A8); theoretical 1D hydrostatic model atmospheres from the ATMO-grid (the 1D equivalent of the STAGGER-grid, see Appendix A of Magic et al. 2013A&A...557A..26M, Cat. J/A+A/557/A26); and theoretical 1D hydrostatic model atmospheres from the MARCS-grid (Gustafsson et al. 2008A&A...486..951G). Table1 contains the line parameters that were adopted for the grids of abundance corrections. Table2 contains the 3D non-LTE versus 1D LTE abundance corrections for CI lines. Table3 contains the 3D non-LTE versus 1D LTE abundance corrections for OI lines. Table4 contains the 3D LTE versus 1D LTE abundance corrections for FeII lines. Table5 contains the 1D non-LTE versus 1D LTE abundance corrections for CI lines. Table6 contains the 1D non-LTE versus 1D LTE abundance corrections for OI lines. Table7 contains the stellar parameters and abundances for the 187 sample stars.
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- ID:
- ivo://CDS.VizieR/J/A+A/639/A145
- Title:
- GALAH survey. FGK binary stars (Traven+, 2020)
- Short Name:
- J/A+A/639/A145
- Date:
- 30 Jun 2020 06:55:32
- Publisher:
- CDS
- Description:
- We here analyse a specific data-set: the extended GALAH dataset. This consists of stellar spectra from the GALAH survey (reduced as explained in Kos et al., 2017MNRAS.464.1259K), apparent magnitudes from a variety of photometric catalogues (AAVSO Photometric All Sky Survey - APASS; Henden et al. 2016, Cat. II/336, Gaia DR2; Gaia Collaboration et al. 2018, Cat. I/345. Two Micron All Sky Survey - 2MASS; Skrutskie et al. 2006, Cat. VII/233, Wide-field Infrared Survey Explorer - WISE; Wright et al. 2010, Cat. II/311), and the parallax measurements from Gaia DR2. The data provided in this catalogue are described in Table A.1 of the paper.
- ID:
- ivo://CDS.VizieR/J/AJ/159/50
- Title:
- Identifying multiple populations in M71 using CN
- Short Name:
- J/AJ/159/50
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have observed their cyanogen CN features at ∼3800 and 4120Å as well as the CH band at ∼4300Å for 145 evolved stars in the Galactic globular cluster M71 using the multi-object spectrograph, Hydra, on the Wisconsin-Indiana-Yale- NOAO-3.5 m telescope. We use these measurements to create two δCN indices finding that both distributions are best fit by two populations: a CN-enhanced and CN-normal. We find that 42%±4% of the red giant branch stars in our sample are CN-enhanced. The percentage of CN-enhanced is 40%±13% for the asymptotic giant branch and 33%±9% for the horizontal branch stars (HB stars), which suggests there are no missing second generation stars at these stages of stellar evolution. The two generations also separate in magnitude and color on the HB, which allows us to find the difference in He abundance between the two populations by fitting appropriate zero-age horizontal branches. The broad range of distances from the cluster's center covered by our sample allows us to study the dependence of the ratio of the number of first to second population stars on the distance from the cluster's center, and we find that this ratio does not vary radially and that the two populations are spatially mixed. Finally, we compare our identification of multiple populations with the classification based on the Na-O anti-correlation and the Hubble Space Telescope UV photometry, and we find good agreement with both methods.
- ID:
- ivo://CDS.VizieR/J/ApJ/872/16
- Title:
- Integrated star formation law revisited. I.
- Short Name:
- J/ApJ/872/16
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use new and updated gas- and dust-corrected star formation rate (SFR) surface densities to revisit the integrated star formation law for local "quiescent" spiral, dwarf, and low surface brightness galaxies. Using UV-based SFRs with individual IR-based dust corrections, we find that "normal" spiral galaxies alone define a tight Σ<SUB>(HI+H2)–Σ</SUB>SFR_ relation described by an n=1.41<SUB>–0.07</SUB><SUP>+0.07</SUP> power law with a dispersion of 0.28<SUB>–0.02</SUB><SUP>+0.02</SUP> (errors reflect fitting and statistical uncertainties). The SFR surface densities are only weakly correlated with HI surface densities alone, exhibiting a stronger and roughly linear correlation with H<SUB>2</SUB> surface densities, similar to what is seen in spatially resolved measurements of disks. However, many dwarf galaxies lie below the star formation law defined by spirals, suggesting a low-density threshold in the integrated star formation law. We consider alternative scaling laws that better describe both spirals and dwarfs. Our improved measurement precision also allows us to determine that much of the scatter in the star formation law is intrinsic, and we search for correlations between this intrinsic scatter and secondary physical parameters. We find that dwarf galaxies exhibit second-order correlations with the total gas fraction, stellar mass surface density, and dynamical time, which may explain much of the scatter in the star formation law. Finally, we discuss various systematic uncertainties that should be kept in mind when interpreting any study of the star formation law, particularly the X(CO) conversion factor and the diameter chosen to define the star-forming disk in a galaxy.
- ID:
- ivo://CDS.VizieR/J/other/Nat/498.198
- Title:
- Na abundances in NGC6752
- Short Name:
- J/other/Nat/498.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The asymptotic giant branch (AGB) phase is the final stage of nuclear burning for low-mass stars. Although Milky Way globular clusters are now known to harbour (at least) two generations of stars, they still provide relatively homogeneous samples of stars that are used to constrain stellar evolution theory. It is predicted by stellar models that the majority of cluster stars with masses around the current turn-off mass (that is, the mass of the stars that are currently leaving the main sequence phase) will evolve through the AGB phase. Here we report that all of the second-generation stars in the globular cluster NGC 6752 - 70 per cent of the cluster population - fail to reach the AGB phase. Through spectroscopic abundance measurements, we found that every AGB star in our sample has a low sodium abundance, indicating that they are exclusively first-generation stars. This implies that many clusters cannot reliably be used for star counts to test stellar evolution timescales if the AGB population is included. We have no clear explanation for this observation.
- ID:
- ivo://CDS.VizieR/J/AJ/110/2288
- Title:
- RR Lyrae Metallicities
- Short Name:
- III/176
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalog presents metal abundance, distance and radial velocity data on a sample of 302 ab-type RR Lyrae variables within about 2.5 kpc of the Sun. The metal abundance information was obtained from low-medium resolution spectra, using the pseudo-equivalent widths of the Ca II K line and the the H-delta, H-gamma and H-beta lines. The technique employed was similar to Preston's (<A HREF="http://simbad.cds.unistra.fr/simbad/sim-ref?bibcode=1959ApJ...130..507P%201959ApJ...130..507P">1959ApJ...130..507P 1959ApJ...130..507P</A>) Δ-S method, though significant differences exist; see the source reference for details. The data were calibrated to the Zinn & West (<A HREF="http://simbad.cds.unistra.fr/simbad/sim-ref?bibcode=1984ApJS...55...45Z%201984ApJS...55...45Z">1984ApJS...55...45Z 1984ApJS...55...45Z</A>) globular cluster abundance scale. The photometry employed in the distance determinations was primarily taken from the General Catalog of Variable Stars (1985, hereafter GCVS4). Exceptions are noted in column 29; the letters match the footnotes in Table 10 of Layden (<A HREF="http://simbad.cds.unistra.fr/simbad/sim-ref?bibcode=1994AJ....108.1016L%201994AJ....108.1016L">1994AJ....108.1016L 1994AJ....108.1016L</A>). The minimum and maximum light photometry, and rise-time were combined following Barnes & Hawley (<A HREF="http://simbad.cds.unistra.fr/simbad/sim-ref?bibcode=1986ApJ...307L...9B%201986ApJ...307L...9B">1986ApJ...307L...9B 1986ApJ...307L...9B</A>) to give an estimate of the intensity- averaged magnitude, i.e. the magnitude the star would have if it were not variable. When the GCVS4 quoted magnitudes in passbands other than V, the GCVS4 magnitudes were transformed to the V passband using the relations established in Layden (<A HREF="http://simbad.cds.unistra.fr/simbad/sim-ref?bibcode=1994AJ....108.1016L%201994AJ....108.1016L">1994AJ....108.1016L 1994AJ....108.1016L</A>). The interstellar absorption estimates are from Burstein & Heiles (<A HREF="http://simbad.cds.unistra.fr/simbad/sim-ref?bibcode=1982AJ.....87.1165B%201982AJ.....87.1165B">1982AJ.....87.1165B 1982AJ.....87.1165B</A>), modified by a simple dust-distribution model. The distances were computed assuming the Mv(RR)-[Fe/H] relation of Carney, Storm & Jones (<A HREF="http://simbad.cds.unistra.fr/simbad/sim-ref?bibcode=1992ApJ...386..663C%201992ApJ...386..663C">1992ApJ...386..663C 1992ApJ...386..663C</A>). Radial velocities were measured from the spectra via cross-correlation with secondary velocity standards. The velocities from the individual spectra were fit with a standard radial velocity curve in the (phase, velocity) plane, to give an estimate of the systemic (center of mass) velocity of each star. The error in this value was estimated from the scatter about the best-fit velocity curve, and the quality of the spectra employed. Other methods were used to combine the individual velocities when the situation demanded (cm = 2,3 in column 70; see Layden (<A HREF="http://simbad.cds.unistra.fr/simbad/sim-ref?bibcode=1994AJ....108.1016L%201994AJ....108.1016L">1994AJ....108.1016L 1994AJ....108.1016L</A>) for details). The observed velocities were combined with values from the literature to produce a final, best estimate of the systemic radial velocity of each star, and its error.
