- ID:
- ivo://CDS.VizieR/J/AJ/161/203
- Title:
- A sample of 7146 M or K-dwarfs from KIC and Gaia
- Short Name:
- J/AJ/161/203
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The planet-metallicity correlation serves as a potential link between exoplanet systems as we observe them today and the effects of bulk composition on the planet formation process. Many observers have noted a tendency for Jovian planets to form around stars with higher metallicities; however, there is no consensus on a trend for smaller planets. Here, we investigate the planet-metallicity correlation for rocky planets in single and multi-planet systems around Kepler M-dwarf and late-K-dwarf stars. Due to molecular blanketing and the dim nature of these low-mass stars, it is difficult to make direct elemental abundance measurements via spectroscopy. We instead use a combination of accurate and uniformly measured parallaxes and photometry to obtain relative metallicities and validate this method with a subsample of spectroscopically determined metallicities. We use the Kolmogorov-Smirnov (K-S) test, Mann-Whitney U-test, and Anderson-Darling (AD) test to compare the compact multiple planetary systems with single-transiting planet systems and systems with no detected transiting planets. We find that the compact multiple planetary systems are derived from a statistically more metal-poor population, with a p-value of 0.015 in the K-S test, a p-value of 0.005 in the Mann-Whitney U-test, and a value of 2.574 in the AD test statistic, which exceeds the derived threshold for significance by a factor of 25. We conclude that metallicity plays a significant role in determining the architecture of rocky planet systems. Compact multiples either form more readily, or are more likely to survive on gigayear timescales, around metal-poor stars.
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- ID:
- ivo://CDS.VizieR/J/AJ/155/240
- Title:
- A spectroscopic survey of field RHB stars
- Short Name:
- J/AJ/155/240
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A metallicity, chemical composition, and kinematic survey has been conducted for a sample of 340 candidate field red horizontal-branch (RHB) stars. Spectra with high resolution and high signal-to-noise ratio were gathered with the McDonald Observatory 2.7 m Tull and the Hobby-Eberly Telescope echelle spectrographs, and were used to determine effective temperatures, surface gravities, microturbulent velocities, [Fe/H] metallicities, and abundance ratios [X/Fe] for seven {alpha} and Fe-group species. The derived temperatures and gravities confirm that at least half of the candidates are true RHB stars, with (average) parameters T_eff_~5000 K and log g~2.5. From the {alpha} abundances alone, the thin and thick Galactic populations are apparent in our sample. Space motions for 90% of the program stars were computed from Hipparcos and Gaia parallaxes and proper motions. Correlations between chemical compositions and Galactic kinematics clearly indicate the existence of both thin-disk and thick-disk RHB stars.
- 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/A+A/565/A21
- Title:
- Astrometric catalog around ultracool dwarfs
- Short Name:
- J/A+A/565/A21
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe the astrometric reduction of images obtained with the FORS2/VLT camera in the framework of an astrometric planet search around 20 M/L-transition dwarfs. We present the correction of systematic errors, the achieved astrometric performance, and a new astrometric catalogue containing the faint reference stars in 20 fields located close to the galactic plane. Remote reference stars are used both to determine the astrometric trajectories of the nearby planet search targets and to identify and correct systematic errors. We detected three types of systematic errors in the FORS2 astrometry: the relative motion of the camera's two CCD chips, errors that are correlated in space, and an error contribution of yet unexplained origin. The relative CCD motion has probably a thermal origin and usually is 0.001-0.010px (0.1-1mas), but sometimes amounts to 0.02-0.05px (3-6mas). This instability and space- correlated errors are detected and mitigated using reference stars. The third component of unknown origin has an amplitude of 0.03-0.14mas and is independent of the observing conditions. We find that a consecutive sequence of 32 images of a well-exposed star over 40min at 0.6arcsec seeing results in a median r.m.s. of the epoch residuals of 0.126mas. Overall, the epoch residuals are distributed according to a normal law with a {chi}^2^ value near unity. We compiled a catalogue of 12000 stars with I-band magnitudes of 16-22 located in 20 fields, each covering 2x2'. It contains I-band magnitudes, ICRF positions with 40-70mas precision, and relative proper motions and absolute trigonometric parallaxes with a precision of 0.1mas/yr and 0.1mas at the bright end, respectively. This work shows that an astrometric accuracy of ~100 micro-arcseconds over two years can be achieved with a large optical telescope in a survey covering several targets and varying observing conditions.
- ID:
- ivo://CDS.VizieR/J/A+A/642/A21
- Title:
- Astrometric parameters for 135 OB stars
- Short Name:
- J/A+A/642/A21
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Our goal is to better understand the origin and the star-formation history of regions NGC 6334 and NGC 6357. We focus our study on the young stars (young stellar objects and OB stars) kinematics in both regions using mainly Gaia-DR2 data. For both regions we compiled OB stars and young stellar objects catalogues from literature and we complemented them using VPHAS+ DR2 and Spitzer IRAC/GLIMPSE photometry catalogues. A cross-match is performed with the Gaia-DR2 catalogue in order to obtain the parallax and transverse motion information. We confirm that NGC 6334 and NGC 6357 are in the far side of the Saggitarius-Carina arm at a distance of 1.76kpc. For NGC 6357, OB stars show strong clustering and ordered star motion with Vlon~-10.7km/s and Vlat ~3.7km/s while for NGC 6334, no significant systemic motion is observed. The OB stars motions and distribution in NGC 6334 suggest to classify it as an association. Ten and two runaway candidates can be related to NGC 6357 and NGC 6334, respectively. The spatial distributions of the runaway candidates in and around NGC 6357 favor a dynamical (and early) ejection during the cluster(s) formation. Because such stars are likely to be ejected during cluster's formation the fact of not observing as many of such stars towards NGC 6334 suggest different formation conditions than for NGC 6357.
- ID:
- ivo://CDS.VizieR/J/AJ/136/452
- Title:
- Astrometric studies of GAT stars
- Short Name:
- J/AJ/136/452
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of astrometric studies in the regions of Groombridge 34A, the Hyades, Aldebaran, Ross 47, BD+5 1668, 81 Cancri, BD+15 2620, Arcturus, Vega, and Ross 248 are presented. Estimates of the absolute parallax of each star are presented and a mass estimate is present for 81 Cancri. Comments include the discussion of the apparent motions of a few previously suggested planetary systems.
- ID:
- ivo://CDS.VizieR/J/AJ/154/147
- Title:
- Astrometry&photometry for late-type dwarfs&subdwarfs
- Short Name:
- J/AJ/154/147
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New, updated, and/or revised CCD parallaxes determined with the Strand Astrometric Reflector at the Naval Observatory Flagstaff Station are presented. Included are results for 309 late-type dwarf and subdwarf stars observed over the 30+ years that the program operated. For 124 of the stars, parallax determinations from other investigators have already appeared in the literature and we compare the different results. Also included here are new or updated VI photometry on the Johnson-Kron-Cousins system for all but a few of the faintest targets. Together with 2MASS JHK_s_ near-infrared photometry, a sample of absolute magnitude versus color and color versus color diagrams are constructed. Because large proper motion was a prime criterion for targeting the stars, the majority turn out to be either M-type subdwarfs or late M-type dwarfs. The sample also includes 50 dwarf or subdwarf L-type stars, and four T dwarfs. Possible halo subdwarfs are identified in the sample based on tangential velocity, subluminosity, and spectral type. Residuals from the solutions for parallax and proper motion for several stars show evidence of astrometric perturbations.
- ID:
- ivo://CDS.VizieR/J/AJ/155/252
- Title:
- Astrometry & photometry of dwarf carbon stars
- Short Name:
- J/AJ/155/252
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Parallaxes are presented for a sample of 20 nearby dwarf carbon stars. The inferred luminosities cover almost two orders of magnitude. Their absolute magnitudes and tangential velocities confirm prior expectations that some originate in the Galactic disk, although more than half of this sample are halo stars. Three stars are found to be astrometric binaries, and orbital elements are determined; their semimajor axes are 1-3 au, consistent with the size of an AGB mass-transfer donor star.
- ID:
- ivo://CDS.VizieR/J/AN/325/740
- Title:
- Astrophysical supplements to ASCC-2.5
- Short Name:
- J/AN/325/740
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The catalogue of stars in the Galactic open cluster areas (CSOCA) is the result of the kinematic (proper motion), photometric and spatial member selection of stars listed in the homogeneous All-sky Compiled Catalogue of 2.5 Million Stars (ASCC-2.5, Cat. <I/280>) within 520 areas with open clusters selected from an on-line release 2.0 of catalogue by Dias et al. (2004, http://www.astro.iag.usp.br/~wilton, Cat. VII/229). The areas represent quadratic fields centered at adopted cluster centers with side lengths of a_cl_[deg]=2*(r_cl_+0.1), where r_cl_ is the determined angular radius of the cluster. For clusters with r_cl_<0.4{deg}, a_cl_=1{deg}. In every cluster area the CSOCA contains the complete list of the ASCC-2.5 stars. The catalog includes accurate J2000 equatorial coordinates, proper motions in the Hipparcos system, BV photometric data in the Johnson system, proper motion, photometric and spatial membership probabilities, and angular distances from the cluster centers for all included stars. If available, trigonometric parallaxes, multiplicity and variability flags from the ASCC-2.5, spectral types (from the ASCC-2.5 or the Tycho-2 Spectral Type Catalog <III/231>), and radial velocities with their errors from the Catalogue of Radial Velocities of Galactic Stars with high precision Astrometric Data (CRVAD, <III/239>) are also given. Since some cluster areas overlap each other some stars are included in the CSOCA several times. The catalogue contains 171319 entries for 149849 stars. Entries are sorted in right ascension J2000 order.
- ID:
- ivo://CDS.VizieR/J/ApJ/867/105
- Title:
- ATLAS all-sky stellar ref. catalog, ATLAS-REFCAT2
- Short Name:
- J/ApJ/867/105
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Asteroid Terrestrial-impact Last Alert System (ATLAS) observes most of the sky every night in search of dangerous asteroids. Its data are also used to search for photometric variability, where sensitivity to variability is limited by photometric accuracy. Since each exposure spans 7.6{deg} corner to corner, variations in atmospheric transparency in excess of 0.01mag are common, and 0.01mag photometry cannot be achieved by using a constant flat-field calibration image. We therefore have assembled an all-sky reference catalog of approximately one billion stars to m~19 from a variety of sources to calibrate each exposure's astrometry and photometry. Gaia DR2 is the source of astrometry for this ATLAS Refcat2. The sources of g, r, i, and z photometry include Pan-STARRS DR1, the ATLAS Pathfinder photometry project, ATLAS reflattened APASS data, SkyMapper DR1, APASS DR9, the Tycho-2 catalog, and the Yale Bright Star Catalog. We have attempted to make this catalog at least 99% complete to m<19, including the brightest stars in the sky. We believe that the systematic errors are no larger than 5mmag rms, although errors are as large as 20mmag in small patches near the Galactic plane.
