- ID:
- ivo://CDS.VizieR/J/AJ/147/86
- Title:
- From binaries to multiples. I. The FG-67 sample
- Short Name:
- J/AJ/147/86
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Data on the multiplicity of F- and G-type dwarf stars within 67pc of the Sun are presented. This distance-limited sample based on the Hipparcos catalog contains 4847 primary stars (targets) with 0.5<V-I_C_<0.8 and is >90% complete. There are 2196 known stellar pairs; some of them belong to 361 hierarchical systems from triples to quintuples. Models of companion detection by radial velocity, astrometric acceleration, direct resolution, and common proper motion are developed. They serve to compute completeness for each target, using the information on its coverage collected here. About 80% of companions to the primary stars are detected, but the census of subsystems in the secondary components is only about 30%. Masses of binary components are estimated from their absolute magnitudes or by other methods; the periods of wide pairs are evaluated from their projected separations. A third of binaries with periods shorter than ~100yr are spectroscopic and/or astrometric pairs with yet unknown periods and mass ratios. These data are used in the accompanying Paper II to derive unbiased statistics of hierarchical multiple systems.
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- ID:
- ivo://CDS.VizieR/J/MNRAS/389/585
- Title:
- Fundamental parameters of M dwarfs
- Short Name:
- J/MNRAS/389/585
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We empirically determine effective temperatures and bolometric luminosities for a large sample of nearby M dwarfs, for which high accuracy optical and infrared photometry is available. We introduce a new technique which exploits the flux ratio in different bands as a proxy of both effective temperature and metallicity. Our temperature scale for late-type dwarfs extends well below 3000K (almost to the brown dwarf limit) and is supported by interferometric angular diameter measurements above 3000K. Our metallicities are in excellent agreement (usually within 0.2dex) with recent determinations via independent techniques. A subsample of cool M dwarfs with metallicity estimates based on hotter Hipparcos common proper motion companions indicates our metallicities are also reliable below 3000K, a temperature range unexplored until now. The high quality of our data allows us to identify a striking feature in the bolometric luminosity versus temperature plane, around the transition from K to M dwarfs. We have compared our sample of stars with theoretical models and conclude that this transition is due to an increase in the radii of the M dwarfs, a feature which is not reproduced by theoretical models.
- ID:
- ivo://CDS.VizieR/J/A+A/638/A104
- Title:
- Gaia DR2 candidate RR Lyrae of Sgr stream & dwarf
- Short Name:
- J/A+A/638/A104
- Date:
- 14 Jan 2022 08:12:04
- Publisher:
- CDS
- Description:
- The Sagittarius (Sgr) stream is one of the best tools that we currently have to estimate the mass and shape of our Galaxy. However, assigning membership and obtaining the phase-space distribution of the stars that form the tails is quite challenging. Our goal is to produce a catalogue of RR Lyrae stars of Sgr and obtain an empiric measurement of the trends along the stream in sky position, distance and tangential velocities. We generate two initial samples from the Gaia DR2 RR Lyrae catalogue: one, selecting only the stars within +/-20{deg} of the orbital plane of Sagittarius (Strip) and the other, the result of applying the Pole Count Map (nGC3) algorithm. We then use the model-independent, deterministic method developed in this work to remove most of the contamination by detecting and isolating the stream in distance and proper motions. The output is two empiric catalogues: the Strip sample (higher-completeness, lower-purity) which contains 11677 stars, and the nGC3 sample (higher-purity, lower-completeness) with 6608 stars. We characterise the changes along the stream in all the available dimensions, the 5 astrometric ones plus the metallicity, covering more than 2{pi}rad in the sky and obtain new estimates for the apocentres and the mean [Fe/H] of the RR Lyrae population. Also, we show the first map of the two components of the tangential velocity, thanks to the combination of distances and proper motions. Finally, we detect the bifurcation in the leading arm and report no significant difference between the two branches, either in metallicity, kinematics or distance. We provide the largest sample of RR Lyrae candidates of Sgr, which can be used as an input for a spectroscopic follow-up or as a reference for the new generation of models of the stream through the interpolators in distance and velocity that we have constructed.
- ID:
- ivo://CDS.VizieR/J/A+A/418/551
- Title:
- Galactic disk stars abundances and velocities
- Short Name:
- J/A+A/418/551
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have performed the detailed analysis of 174 high-resolution spectra of FGK dwarfs obtained with the ELODIE echelle spectrograph at the Observatoire de Haute-Provence. Abundances of Fe, Si and Ni have been determined from equivalent widths under LTE approximation, whereas abundances of Mg have been determined under NLTE approximation using equivalent widths of 4 lines and profiles of 5 lines. Spatial velocities with an accuracy better than 1kms, as well as orbits, have been computed for all stars.
- ID:
- ivo://CDS.VizieR/J/A+AS/129/237
- Title:
- G and K dwarfs abundances
- Short Name:
- J/A+AS/129/237
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The table presents the abundances of all 47 dwarf stars analysed in the paper. We give abundances relative to the Sun in the standard notation of [X/H]=log(X/H)_star_-log(X/H)_{sun}_. The 5 K dwarf stars and 3 stars in common with Barbuy & Grenon (1990) appear at the end of the table. The label of each column indicates the ion the quoted abundances are derived from. For each star we give the abundance, [X/H], the line-to-line scatter (if more than one line is used) and the number of lines used. The stars are ordered in the same way as in Table 1 in the paper, ie. the K dwarf stars and the stars in common with Barbuy & Grenon (1990) are found at the end.
- ID:
- ivo://CDS.VizieR/J/MNRAS/336/879
- Title:
- G and K dwarfs UBV(RI)c and ubvy photometry
- Short Name:
- J/MNRAS/336/879
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- K dwarfs have lifetimes older than the present age of the Galactic disc, and are thus ideal stars for investigating the chemical evolution of the disc. We have developed several photometric metallicity indicators for K dwarfs, based on a sample of accurate spectroscopic metallicities for 34 disc and halo G and K dwarfs. The photometric metallicities lead us to develop a metallicity index for K dwarfs based only on their position in the colour-absolute-magnitude diagram. Metallicities have been determined for 431 single K dwarfs drawn from the Hipparcos catalogue, selecting the stars by absolute magnitude and removing multiple systems. The sample is essentially a complete reckoning of the metal content in nearby K dwarfs. We use stellar isochrones to mark the stars by mass, and select a subset of 220 of the stars, which is complete within a narrow mass interval. We fit the data with a model of the chemical evolution of the solar cylinder. We find that only a modest cosmic scatter is required to fit our age-metallicity relation. The model assumes two main infall episodes for the formation of the halo-thick disc and thin disc, respectively. The new data confirm that the solar neighbourhood formed on a long time-scale of the order of 7Gyr.
- ID:
- ivo://CDS.VizieR/J/MNRAS/444/2251
- Title:
- G0-G3 main-sequence stars with V<15
- Short Name:
- J/MNRAS/444/2251
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The basic stellar atmospheric parameters (effective temperature, surface gravity and global metallicity) were determined simultaneously for a sample of 233 stars, limited in magnitude (V<15), with spectral types between G0 and G3 and luminosity class V (main sequence). The analysis was based on spectroscopic observations collected at the Observatorio Astrofisico Guillermo Haro and using a set of Lick-like indices defined in the spectral range 3800-4800{AA}. An extensive set of indices computed in a grid of theoretical spectra was used as a comparison tool in order to determine the photospheric parameters. The method was validated by matching the results from spectra of the asteroids Vesta and Ceres with the Sun parameters. The main results were as follows: (i) the photospheric parameters were determined for the first time for 213 objects in our sample and (ii) a sample of 20 new super-metal-rich star candidates was found.
- ID:
- ivo://CDS.VizieR/J/ApJ/691/342
- Title:
- griBVI photometry in M37
- Short Name:
- J/ApJ/691/342
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In the course of conducting a deep (14.5<~r<~23), 20 night survey for transiting planets in the rich ~550Myr old open cluster M37, we have measured the rotation periods of 575 stars, which lie near the cluster main sequence, with masses 0.2M_{sun}_<~M<~1.3M_{sun}_. This is the largest sample of rotation periods for a cluster older than 500Myr. Using this rich sample we investigate a number of relations between rotation period, color, and the amplitude of photometric variability.
- ID:
- ivo://CDS.VizieR/II/24
- Title:
- H-{alpha} Photometry of Northern Late-Type Stars I.
- Short Name:
- II/24
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Observations are presented of the strength of the H-{alpha} absorption line in the spectra of approximately 600 northern F, G and K stars of differing luminosities and chemical compositions. Most of the stars in this catalogue were previously observed by Griffin and Redman (1960MNRAS.120..287G), Deeming (1960MNRAS.121...52D), and Griffin (1961MNRAS.122..181G). Data given in this catalog include HD number, MK spectral classification, high velocity, (B-V) color index, magnesium b ratio, sodium D line ratio and H-{alpha} ratio.
- ID:
- ivo://CDS.VizieR/II/22
- Title:
- H{alpha} photometry of Southern F-G dwarfs
- Short Name:
- II/22
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- H{alpha} photometry is presented for 172 southern F, G, and K type stars, mostly of luminosity classes V and IV. The bands measured, using a spectroscopic resolution of 3.4{AA}/mm, were: H{alpha}: 6546.5-6582.5{AA} comparison regions: 6469.0-6505.0{AA} and 6624.0-6660.0{AA}.
