- 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].
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- 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/441/1149
- Title:
- Abundances of 20 F-G disk stars
- Short Name:
- J/A+A/441/1149
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Mn, Co and Eu abundances for a sample of 20 disk F and G dwarfs and subgiants with metallicities between -0.8 and +0.3. We investigate the influence of hyperfine structure (HFS) on the derived abundances of Mn and Co by using HFS data from different sources in the literature, as well as calculated HFS from interaction factors A and B.
- 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/145/52
- Title:
- Abundances of late K and M dwarfs in binary systems
- Short Name:
- J/AJ/145/52
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Knowledge of late K and M dwarf metallicities can be used to guide planet searches and constrain planet formation models. However, the determination of metallicities of late-type stars is difficult because visible wavelength spectra of their cool atmospheres contain many overlapping absorption lines, preventing the measurement of equivalent widths. We present new methods, and improved calibrations of existing methods, to determine metallicities of late K and M dwarfs from moderate resolution (1300<R<2000) visible and infrared spectra. We select a sample of 112 wide binary systems that contain a late-type companion to a solar-type primary star. Our sample includes 62 primary stars with previously published metallicities, as well as 50 stars with metallicities determined from our own observations. We use our sample to empirically determine which features in the spectrum of the companion are best correlated with the metallicity of the primary. We find ~120 features in K and M dwarf spectra that are useful for predicting metallicity. We derive metallicity calibrations for different wavelength ranges, and show that it is possible to get metallicities reliable to <0.10dex using either visible, J-, H-, or K-band spectra. We find that the most accurate metallicities derived from visible spectra requires the use of different calibrations for early-type (K5.5-M2) and late-type (M2-M6) dwarfs. Our calibrations are applicable to dwarfs with metallicities of -1.04<[Fe/H]<+0.56 and spectral types from K7 to M5. Lastly, we use our sample of wide binaries to test and refine existing calibrations to determine M dwarf metallicities. We find that the {zeta} parameter, which measures the ratio of TiO can CaH bands, is correlated with [Fe/H] for super-solar metallicities, and {zeta} does not always correctly identify metal-poor M dwarfs. We also find that existing calibrations in the K and H bands are quite reliable for stars with [Fe/H]>-0.5, but are less useful for more metal-poor stars.
- ID:
- ivo://CDS.VizieR/V/89
- Title:
- Ages, Metallicities, Galactic Orbit of F stars
- Short Name:
- V/89
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Absolute magnitudes, metallicities, effective temperatures, surface gravities, distances, and tangential velocities are calculated for 5498 F stars with homogeneous data on uvby photometry and proper motion, and placed within 80 pc from the Sun. Components of space velocities, eccentricities of galactic orbits, perigalactic and apogalactic distances, and maximal remotness from galactic plane are presented for 1787 stars. Isochrone ages are determined for 3405 slightly evolved stars proceeding from Revised Yale isochrones.
- ID:
- ivo://CDS.VizieR/J/A+A/653/A98
- Title:
- asPIC1.1 catalogue
- Short Name:
- J/A+A/653/A98
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- The ESA PLAnetary Transits and Oscillations of stars (PLATO) mission will search for terrestrial planets in the habitable zone of solar-like stars. Because of telemetry limitations PLATO targets need to be pre-selected. In this paper we present an all sky catalog that will be fundamental to select the best PLATO fields and the most promising target stars, derive their fundamental parameters, analyze the instrumental performances and then plan and optimize follow-up observations. This catalog also represents a valuable resource for the general definition of stellar samples optimized for the search of transiting planets. We used Gaia Data Release 2 (DR2) astrometry and photometry and 3D maps of the local interstellar medium to isolate FGK (V<=13) and M(V<=16) dwarfs and subgiant stars. We present the first public release of the all sky PLATO Input Catalog (asPIC1.1) containing a total of 2675539 stars among which 2378177 FGK dwarfs and subgiants and 297362 M dwarfs. The median distance in our sample is 428pc for FGK stars and 146 pc for M dwarfs, respectively. We derived the reddening of our targets and developed an algorithm to estimate stellar fundamental parameters (Teff, radius, mass) from astrometric and photometric measurements. We show that our overall (internal+external) uncertainties on the stellar parameters determination is ~230K (4%) for the effective temperatures, ~0.1R_{sun}_ (9%) for the stellar radii and ~0.1M_{sun}_ (11%) for the stellar mass. We release a special target list containing all known planet hosts cross-matched with our catalog.
- ID:
- ivo://CDS.VizieR/J/AJ/147/137
- Title:
- Atmospheric parameters in luminous stars
- Short Name:
- J/AJ/147/137
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Parameters and abundances for 451 stars of spectral types F, G, and K of luminosity classes I and II have been derived. Absolute magnitudes and E(B-V) have been derived for the warmer stars in order to investigate the galactic abundance gradient. The value found here: d[Fe/H]/dR~-0.06dex/kpc, agrees well with previous determinations. Stellar evolution indicators have also been investigated with the derived C/O ratios indicating that standard CN processing has been operating. Perhaps the most surprising result found in these supposedly relatively young intermediate-mass stars is that both [O/Fe] and [C/Fe] show a correlation with [Fe/H] much the same as found in older populations. While the stars were selected based on luminosity class, there does exist a significant [Fe/H] range in the sample. The likely explanation of this is that there is a significant range in age in the sample; that is, some of the sample are low-mass red-giant stars with types that place them within the selection criteria.
- ID:
- ivo://CDS.VizieR/J/MNRAS/434/1422
- Title:
- Atmospheric param. of 169 FGKM stars
- Short Name:
- J/MNRAS/434/1422
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The asteroseismic and planetary studies, like all research related to stars, need precise and accurate stellar atmospheric parameters as input. We aim at deriving the effective temperature (Teff), the surface gravity (logg), the metallicity ([Fe/H]), the projected rotational velocity (vsini) and the MK type for 169 F-, G-, K- and M-type Kepler targets which were observed spectroscopically from the ground with five different instruments. We use two different spectroscopic methods to analyse 189 high-resolution, high-signal-to-noise spectra acquired for the 169 stars. For 67 stars, the spectroscopic atmospheric parameters are derived for the first time. KIC 9693187 and 11179629 are discovered to be double-lined spectroscopic binary systems. The results obtained for those stars for which independent determinations of the atmospheric parameters are available in the literature are used for a comparative analysis. As a result, we show that for solar-type stars the accuracy of present determinations of atmospheric parameters is +/-150K in Teff, +/-0.15dex in [Fe/H] and +/-0.3dex in logg. Finally, we confirm that the curve-of-growth analysis and the method of spectral synthesis yield systematically different atmospheric parameters when they are applied to stars hotter than 6000K.
- ID:
- ivo://CDS.VizieR/J/AJ/150/77
- Title:
- Catalog of hypervelocity candidate stars
- Short Name:
- J/AJ/150/77
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper we analyze a sample of metal-rich (>-0.8dex) main sequence stars in the extended solar neighborhood, investigating kinematic outliers from the background population. The data, which are taken from the Sloan Digital Sky Survey, are kinematically profiled as a function of distance from the Galactic plane using full six-dimensional phase space information. Each star is examined in the context of these kinematic profiles and likelihoods are assigned to quantify whether a star matches the underlying profile. Since some of these stars are likely to have been ejected from the disk, we trace back their orbits in order to determine potential ejection radii. We find that objects with low probability (i.e., "outliers") are typically more metal-poor, faster and, most importantly, have a tendency to originate from the inner Galaxy compared to the underlying population. We also compose a sample of stars with velocities exceeding the local escape velocity. Although we do not discount that our sample could be contaminated by objects with spurious proper motions, a number of stars appear to have been ejected from the disk with exceptionally high velocities. Some of these are consistent with being ejected from the spiral arms and hence are a rich resource for further study. Finally we look at objects whose orbits are consistent with them being ejected at high speeds from the Galactic center. Of these objects we find that one, J135855.65+552538.19, is inconsistent with halo, bulge and disk kinematics and could plausibly have been ejected from the Galactic nucleus via a Hills mechanism.
