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- ID:
- ivo://CDS.VizieR/J/A+A/506/729
- Title:
- Abundances in globular cluster Pal 3
- Short Name:
- J/A+A/506/729
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Chemical abundances of 25 alpha-, iron peak-, and neutron-capture elements in the remote (R=90kpc) outer halo globular cluster have been determined for 4 red giants observed with the Magellan/MIKE spectrograph and from integrated spectra of 19 stars obtained with the Keck/HIRES instrument. The resulting abundance ratios show that Pal 3 is very similar to globular clusters of the inner halo and very dissimilar from dwarf spheroidal galaxy stars. Its neutron capture element ratios are compatible with a pure r-process enrichment.
- ID:
- ivo://CDS.VizieR/J/A+A/326/1069
- Title:
- Abundances in globular clusters
- Short Name:
- J/A+A/326/1069
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Tables 5, 6, and 7 present details of the derived abundances for the stars observed in the globular clusters M2, M13, and M56, respectively. Table 9 gives the measured equivalent widths for the iron lines of the field stars. Table 10 gives the measured equivalent widths for the programme stars of this survey.
- ID:
- ivo://CDS.VizieR/J/ApJ/736/87
- Title:
- Abundances in G-type stars with exoplanets
- Short Name:
- J/ApJ/736/87
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We confirm the difference in chemical abundance between stars with and without exoplanets and present the relation between chemical abundances and physical properties of exoplanets, such as planetary mass and the semimajor axis of planetary orbit. We obtained the spectra of 52 G-type stars from the Bohyunsan Optical Astronomy Observatory (BOAO) Echelle Spectrograph and carried out abundance analyses for 12 elements: Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Co, and Ni. We first found that the [Mn/Fe] ratios of planet-host stars are higher than those of comparison stars over the entire metallicity range, and we then found that in metal-poor stars of [Fe/H]<-0.4 the abundance difference was larger than in metal-rich samples, especially for the elements of Mg, Al, Sc, Ti, V, and Co. After examining the relation between planet properties and metallicities of planet-host stars, we observed that planet-host stars with low metallicities tend to have several low-mass planets (<M_J_) instead of a massive gas-giant planet.
- ID:
- ivo://CDS.VizieR/J/MNRAS/424/2316
- Title:
- Abundances in HII regions
- Short Name:
- J/MNRAS/424/2316
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We suggest a new way of determining abundances and electron temperatures in HII regions from strong emission lines. Our approach is based on the standard assumption that HII regions with similar intensities of strong emission lines have similar physical properties and abundances. A 'counterpart' for a studied HII region may be chosen among HII regions with well-measured abundances (reference HII regions) by comparison of carefully chosen combinations of strong-line intensities. Then the abundances in the investigated HII region can be assumed to be the same as those in its counterpart. In other words, we suggest to determine the abundances in HII regions 'by precedent'. To get more reliable abundances for the considered HII region, a number of reference HII regions are selected and then the abundances in the target HII region are estimated through extrapolation/interpolation. We will refer to this method of abundance determination as the counterpart method or, for brevity, the C method. We define a sample of reference HII regions and verify the validity of the C method. We find that this method produces reliable abundances. Finally, the C method is used to obtain the radial abundance distributions in the extended discs of the spiral galaxies M83, NGC 4625 and NGC 628.
- ID:
- ivo://CDS.VizieR/J/A+A/464/885
- Title:
- Abundances in 53 HII regions
- Short Name:
- J/A+A/464/885
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Continuing the systematic determination of the electron temperature of HII regions using the Balmer and/or Paschen discontinuities by Guseva et al. (2006ApJ...644..890G) we focus here on 3.6m ESO telescope observations of a large new sample of 69 HII regions in 45 blue compact dwarf (BCD) galaxies. This data set spans a wide range in metallicity (Z_{sun}_/60<Z<Z_{sun}_/3) and, combined with the sample of 47 HII regions from Guseva et al. (2006ApJ...644..890G), yields the largest spectroscopic data set ever used to derive the electron temperature in the H^+^ zone. In the same way as in Guseva et al. (2006ApJ...644..890G) we have used a Monte Carlo technique to vary free parameters and to calculate a series of model spectral energy distributions (SEDs) for each HII region. The electron temperature in the H^+^ zones was derived from the best fitting synthetic and observed SEDs in the wavelength range ~3200-5100{AA}, which includes the Balmer jump. On the base of the present large spectroscopic sample we find that in hot (Te(H^+^)>11000K) HII regions the temperature of the O^2+^ zone, determined from doubly ionised oxygen forbidden lines, does not differ statistically from the temperature of the H^+^ zone. Thus, we confirm and strengthen the finding by Guseva et al. (2006ApJ...644..890G). We emphasize that due to a number of modelling assumptions and the observational uncertainties for individual objects, only a large, homogeneous sample, as the one used here, can enable a conclusive study of the relation between Te(H^+^) and Te(OIII).
- ID:
- ivo://CDS.VizieR/J/A+A/521/A3
- Title:
- Abundances in HII regions and PNe of M81
- Short Name:
- J/A+A/521/A3
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- M81 is an ideal laboratory to investigate the galactic chemical and dynamical evolution through the study of its young and old stellar populations. We analyze the chemical abundances of planetary nebulae and HII regions in the M81 disk for insight on galactic evolution, and compare it with that of other galaxies, including the Milky Way.
- ID:
- ivo://CDS.VizieR/J/A+A/567/A88
- Title:
- Abundances in HII regions of M81
- Short Name:
- J/A+A/567/A88
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new set of weak-line abundances of HII regions in M81, based on Gemini Multi-Object Spectrograph (GMOS) observations. The aim is to derive plasma and abundance analysis for a sizable set of emission-line targets to study the galactic chemical contents in the framework of galactic metallicity gradients. We used the weak-line abundance approach by deriving electron density and temperatures for several HII regions in M81. Gradient analysis is based on oxygen abundances. Together with a set of HII region abundances determined similarly by us with Multi-Mirror Telescope (MMT) spectra, the new data yield to a radial oxygen gradient of -0.088+/-0.013dex/kpc, which is steeper than the metallicity gradient obtained for planetary nebulae (-0.044+/-0.007dex/kpc). This result could be interpreted as gradient evolution with time: Models of galactic evolution with inside-out disk formation associated to pre-enriched gas infall would produce such difference of gradients, although stellar migration effects would also induce a difference in the metallicity gradients between the old and young populations.
- ID:
- ivo://CDS.VizieR/J/ApJ/768/L12
- Title:
- Abundances in host stars XO-2S and XO-2N
- Short Name:
- J/ApJ/768/L12
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- With the aim of connecting the compositions of stars and planets, we present the abundances of carbon and oxygen, as well as iron and nickel, for the transiting exoplanet host star XO-2N and its wide-separation binary companion XO-2S. Stellar parameters are derived from high-resolution, high signal-to-noise spectra, and the two stars are found to be similar in their T_eff_, log g, iron ([Fe/H]), and nickel ([Ni/H]) abundances. Their carbon ([C/H]) and oxygen ([O/H]) abundances also overlap within errors, although XO-2N may be slightly more C-rich and O-rich than XO-2S. The C/O ratios of both stars (~0.60+/-0.20) may also be somewhat larger than solar (C/O~0.50). The XO-2 system has a transiting hot Jupiter orbiting one binary component but not the other, allowing us to probe the potential effects planet formation might have on the host star composition. Additionally, with multiple observations of its atmosphere the transiting exoplanet XO-2b lends itself to compositional analysis, which can be compared to the natal chemical environment established by our binary star elemental abundances. This work sets the stage for determining how similar or different exoplanet and host star compositions are, and the implications for planet formation, by discussing the C/O ratio measurements in the unique environment of a visual binary system with one star hosting a transiting hot Jupiter.
- ID:
- ivo://CDS.VizieR/J/AZh/77/96
- Title:
- Abundances in Hyades red giants
- Short Name:
- J/AZh/77/96
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- CCD spectra are obtained in 1994-1997 on the 2.6-m telescope of the Crimean Astrophysical observatory in the first chamber of the Coude focus. The dispersion was 3{AA}/mm and the signal-to-noise ratios were 100-300.
