- ID:
- ivo://CDS.VizieR/J/ApJS/234/31
- Title:
- Carbon stars from LAMOST using machine learning
- Short Name:
- J/ApJS/234/31
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this work, we present a catalog of 2651 carbon stars from the fourth Data Release (DR4) of the Large Sky Area Multi-Object Fiber Spectroscopy Telescope (LAMOST). Using an efficient machine-learning algorithm, we find these stars from more than 7 million spectra. As a by-product, 17 carbon-enhanced metal- poor turnoff star candidates are also reported in this paper, and they are preliminarily identified by their atmospheric parameters. Except for 176 stars that could not be given spectral types, we classify the other 2475 carbon stars into five subtypes: 864 C-H, 226 C-R, 400 C-J, 266 C-N, and 719 barium stars based on a series of spectral features. Furthermore, we divide the C-J stars into three subtypes, C-J(H), C-J(R), and C-J(N), and about 90% of them are cool N-type stars as expected from previous literature. Besides spectroscopic classification, we also match these carbon stars to multiple broadband photometries. Using ultraviolet photometry data, we find that 25 carbon stars have FUV detections and that they are likely to be in binary systems with compact white dwarf companions.
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- ID:
- ivo://CDS.VizieR/J/A+A/627/A161
- Title:
- CARMENES stars multi wavelength measurements
- Short Name:
- J/A+A/627/A161
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present precise photospheric parameters of 282 M dwarfs determined from fitting the most recent version of PHOENIX models to high-resolution CARMENES spectra in the visible (0.52-0.96um) and near-infrared wavelength range (0.96-1.71um). With its aim to search for habitable planets around M dwarfs, several planets of different masses have been detected. The characterization of the target sample is important for the ability to derive and constrain the physical properties of any planetary systems that are detected. As a continuation of previous work in this context, we derived the fundamental stellar parameters effective temperature, surface gravity, and metallicity of the CARMENES M-dwarf targets from PHOENIX model fits using a {chi}^2^ method. We calculated updated PHOENIX stellar atmosphere models that include a new equation of state to especially account for spectral features of low-temperature stellar atmospheres as well as new atomic and molecular line lists. We show the importance of selecting magnetically insensitive lines for fitting to avoid effects of stellar activity in the line profiles. For the first time, we directly compare stellar parameters derived from multi wavelength range spectra, simultaneously observed for the same star. In comparison with literature values we show that fundamental parameters derived from visible spectra and visible and near-infrared spectra combined are in better agreement than those derived from the same spectra in the near-infrared alone.
- ID:
- ivo://CDS.VizieR/J/A+A/656/A162
- Title:
- CARMENES stellar atmospheric parameters
- Short Name:
- J/A+A/656/A162
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- We determine effective temperatures, surface gravities, and metallicities for a sample of 343 M dwarfs observed with CARMENES, the double-channel, high-resolution spectrograph installed at the 3.5m telescope at Calar Alto Observatory. We employed SteParSyn, a Bayesian spectral synthesis implementation, along with a grid of synthetic spectra based on BT-Settl model atmospheres and the radiative transfer code turbospectrum. The synthetic grid was computed around 75 magnetically insensitive TiI and FeI along with the TiO gamma- and epsilon-bands. To avoid degeneracies in the parameter space, we imposed Bayesian priors based on multi-band photometric data available for the sample.
- ID:
- ivo://CDS.VizieR/J/A+A/657/A87
- Title:
- CASCADES I. Sample definition and first results
- Short Name:
- J/A+A/657/A87
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- Following the first discovery of a planet orbiting a giant star in 2002, we started the CORALIE radial-velocity search for companions around evolved stars (CASCADES). We present the observations of three stars conducted at the 1.2m Leonard Euler Swiss telescope at La Silla Observatory, Chile, using the CORALIE spectrograph. We aim to detect planetary companions to intermediate-mass G- and K- type evolved stars and perform a statistical analysis of this population. We searched for new planetary systems around the stars HD22532 (TIC200851704), HD64121 (TIC264770836), and HD69123 (TIC146264536). We have followed a volume-limited sample of 641 red giants since 2006 to obtain high-precision radial-velocity measurements. We used the Data & Analysis Center for Exoplanets (DACE) platform to perform a radial-velocity analysis to search for periodic signals in the line profile and activity indices, to distinguish between planetary-induced radial-velocity variations and stellar photospheric jitter, and to search for significant signals in the radial-velocity time series to fit a corresponding Keplerian model. In this paper, we present the survey in detail, and we report on the discovery of the first three planets of the sample around the giant stars HD22532, HD64121, and HD69123.
- 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.
- ID:
- ivo://CDS.VizieR/III/200B
- Title:
- Catalogue of [Fe/H]
- Short Name:
- III/200B
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The catalogue includes [Fe/H] determinations and atmospheric parameters (Teff, logg ) obtained from high resolution spectroscopic observations and detailed analyses, most of them carried out with the help of model-atmospheres. This fifth Edition of the catalogue contains 5946 determinations for 3247 stars, including 751 stars in 84 associations, clusters or galaxies. The literature (700 bibliographical references) is complete up to December 1995. The Catalogue is made up of three tables : Table 1 : field stars Table 2 : stars in galactic associations and clusters, and in SMC, LMC, M33 Table 3 : numbered list of bibliographical references
- ID:
- ivo://CDS.VizieR/III/221A
- Title:
- Catalogue of [Fe/H] of F, G, K stars
- Short Name:
- III/221A
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The catalogue presented here is a compilation of published atmospheric parameters (Teff, logg, [Fe/H]) obtained from high resolution, high signal-to-noise spectroscopic observations. This new edition has changed compared to the five previous versions. It is now restricted to intermediate and low-mass stars (F, G, and K stars). It contains 6354 determinations of (Teff, logg, [Fe/H]) for 3356 stars, including 899 stars in 79 stellar systems. The literature is complete between January 1980 and December 2000 and includes 378 references. The catalogue is made up of two tables, one for field stars and one for stars in galactic associations, open and globular clusters and external galaxies.
- ID:
- ivo://CDS.VizieR/J/AZh/82/453
- Title:
- Catalogue of spectroscopic abundances in stars
- Short Name:
- J/AZh/82/453
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We submit the compiled catalogue of effective temperatures, surface gravities, abundances of iron and magnesium, distances, velocity components, and orbital parameters for stars of solar vicinity. Atmospheric parameters and iron abundances was determined by averaging of published values, which was found from synthetic analysis of high resolution spectra on the basis of 1809 determination from 31 publications. Relative magnesium abundances for 876 dwarfs and subgiants were determined as a result of three-step iteration procedure of averaging with giving weight to each publication and each individual determination. The systematic shifts for each scale relative to reduced main scale was taken into account. We suppose that survey completeness of publications with volume more than 5 stars up to December 2003 is 90%. Spatial velocity components for most majority stars were determined on the stellar data from present day high-precision observations. Galactic orbital parameter were calculated using the Galactic model, which includes a spherical bulge, disk, and extended massive halo.
- ID:
- ivo://CDS.VizieR/III/121
- Title:
- Catalogue of stellar abundances
- Short Name:
- III/121
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The catalogue, compiled at the Torun Observatory, contains the published abundances.
- ID:
- ivo://CDS.VizieR/J/A+A/356/529
- Title:
- Catalogue of wide binaries
- Short Name:
- J/A+A/356/529
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The list contains a total of 131 binaries (115 systems) belonging to the halo or high-velocity disk. Of these, 122 correspond to wide binaries, that is, binaries with expected major semiaxes larger than 25 AU. The catalogue was constructed by identifying common proper-motion companions to the high-velocity and metal-poor stars studied by Schuster and collaborators (SN: Schuster and Nissen 1988A&AS...73..225S, SPC: Schuster, Parrao and Contreras, 1993, Cat. <J/A+AS/97/951>). Based on Stromgren photometry, Schuster et al. obtained distances, metallicities and ages for their stars. For each star of the SN and SPC catalogues a machine search for common proper-motion companions was made among the NLTT (Cat. <I/98>) stars within 12 minutes of arc. This initial list was checked to avoid errors due to misidentifications, duplicate entries, etc., and was supplemented with some companions listed in the LDS (Luyten, 1987, Cat. <I/130>) and not present in the NLTT (mostly from the southern hemisphere), as well as with additional common-proper- motion companions found in the CCDM (Dommanget and Nys, 1994, Cat. <I/211>). Additional close companions found in the CCDM were retained only if an orbit was given, or if their separations were of less than 1". Wider companions were usually eliminated, unless convincing evidence of their sharing the proper motion of the primary was found. Distances to the primaries were updated using the Hipparcos (Cat. <I/239>) catalogue. The data in the list are as follows (for details see the main paper): The first column contains the Hipparcos number, when available. Column 2 contains other identifications of the star. In the third column its multiplicity is indicated. Column 4 contains the adopted distance to the star. Columns 5 and 6 contain the absolute visual magnitudes of the primary and secondary, respectively. The angular separation between the components is given in Column 7, and the expected value of the major semiaxes in Column 8. Columns 9 and 10 contain the metallicity of the primary and its age, as determined by Schuster and collaborators. The individual ages listed were kindly provided by W. J. Schuster. The peculiar velocity of the binary is given in Column 11. Columns 12 to 15 contain the main galactic orbital parameters; we list the apocentric distance, Rmax, as well as the maximum distance away from the galactic plane reached by the star |zmax|, and the three-dimensional eccentricity e of its galactic orbit. The last column contains various notes.
