- ID:
- ivo://CDS.VizieR/J/ApJ/834/142
- Title:
- Gould's Belt Distances Survey (GOBELINS). II. OMC
- Short Name:
- J/ApJ/834/142
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of the Gould's Belt Distances Survey of young star-forming regions toward the Orion Molecular Cloud Complex. We detected 36 young stellar objects (YSOs) with the Very Large Baseline Array, 27 of which have been observed in at least three epochs over the course of two years. At least half of these YSOs belong to multiple systems. We obtained parallax and proper motions toward these stars to study the structure and kinematics of the Complex. We measured a distance of 388+/-5pc toward the Orion Nebula Cluster, 428+/-10pc toward the southern portion L1641, 388+/-10pc toward NGC 2068, and roughly ~420pc toward NGC 2024. Finally, we observed a strong degree of plasma radio scattering toward {lambda} Ori.
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212. GPM1 catalogue
- ID:
- ivo://CDS.VizieR/J/A+AS/121/243
- Title:
- GPM1 catalogue
- Short Name:
- J/A+AS/121/243
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- GPM1 is the first version of the General Compiled Catalogue of Absolute Proper Motions for a sample of HIPPARCOS stars, derived with respect to galaxies within the plan called Catalogue of Faint Stars (KSZ, Deutch A.N., 1952IAUT....8..789D). The programme was proposed for several observatories of the former Soviet Union, China, Rumania and Spain. There are some resulting individual catalogues of absolute proper motions of stars compiled at five observatories (Kiev, Pulkovo, Moscow, Tashkent and Shanghai). The principal aim of the GPM1 construction was to provide absolute proper motions of stars to determine the rotation of the HIPPARCOS system. The GPM1 catalogue comprises absolute proper motions for 977 stars in 180 areas north of -25 degrees of declination. The mean square error is 8mas/yr on average. The standard errors differ from one star to another one depending on the number and quality of individual catalogues. They have been computed and presented for each star. For a single GPM1 field the absolute zero-point error of linking proper motions to the galaxies is 3mas/yr on average. The error of such a kind depends on the number and compactness of the galaxies available in each field. In addition to absolute proper motions and their mean errors, the catalogue gives the following data for each star: right ascension, declination, epoch for position, V-magnitude and number, copied from HIC. The stars were also identified with the objects of the Smithsonian Astrophysical Observatory Star Catalogue (SAO) list. Positions are given for equator and equinox J2000.0 on the system of FK5. They were presented to identify the GPM1 stars with those from other catalogues. The data file is sorted by J2000.0 right ascensions.
- ID:
- ivo://CDS.VizieR/J/MNRAS/471/1446
- Title:
- Ground-based proper motion of 12 nearby GC
- Short Name:
- J/MNRAS/471/1446
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We derive relative proper motions of stars in the fields of the globular clusters M12, NGC 6362, M4, M55, M22, NGC 6752, NGC 3201, M30, M10, NGC 362, M5 and 47 Tucanae based on data collected between 1997 and 2015 with the 1-m Swope telescope of Las Campanas Observatory. We determine membership class and membership probability for over 446000 objects, and show that these are efficient methods for separating field stars from members of the cluster. In particular, membership probabilities of variable stars and blue/yellow/red stragglers are determined. Finally, we find absolute proper motions for six globular clusters from our sample: M55, NGC 3201, M10, NGC 362, M5 and 47 Tuc. An electronic catalogue of the derived proper motions is publicly available via the internet.
- ID:
- ivo://CDS.VizieR/J/PASP/114/233
- Title:
- h and {chi} Per memberships
- Short Name:
- J/PASP/114/233
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A segregation between cluster members and field stars in the region of the double cluster h and {chi} Persei is accomplished working from proper motions and positions as kinematic random variables. The extinction R_V_ and the distance moduli are determined once the physical cluster members are found.
- ID:
- ivo://CDS.VizieR/J/ApJS/201/19
- Title:
- Hawaii Infrared Parallax Program. I.
- Short Name:
- J/ApJS/201/19
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Astrometry and photometry for 318 ultracool dwarfs in 265 systems that have measured trigonometric parallaxes. To be included in this tabulation, an object must have a spectral type >=M6 or a K-band absolute magnitude >8.5mag. Parallaxes, proper motions, and coordinates at a specified epoch are given for all objects. Photometric measurements in MKO, 2MASS, Spitzer, and WISE systems are given when available. Various other flags that provide additional information about the object or photometry are included.
- ID:
- ivo://CDS.VizieR/J/ApJ/833/96
- Title:
- Hawaii infrared parallax program. II. Ultracool dwarfs
- Short Name:
- J/ApJ/833/96
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a large, uniform analysis of young (~10-150Myr) ultracool dwarfs, based on new high-precision infrared (IR) parallaxes for 68 objects. We find that low-gravity (VL-G) late-M and L dwarfs form a continuous sequence in IR color-magnitude diagrams, separate from the field population and from current theoretical models. These VL-G objects also appear distinct from young substellar (brown dwarf and exoplanet) companions, suggesting that the two populations may have a different range of physical properties. In contrast, at the L/T transition, young, old, and spectrally peculiar objects all span a relatively narrow range in near-IR absolute magnitudes. At a given spectral type, the IR absolute magnitudes of young objects can be offset from ordinary field dwarfs, with the largest offsets occurring in the Y and J bands for late-M dwarfs (brighter than the field) and mid-/late-L dwarfs (fainter than the field). Overall, low-gravity (VL-G) objects have the most uniform photometric behavior, while intermediate gravity (INT-G) objects are more diverse, suggesting a third governing parameter beyond spectral type and gravity class. We examine the moving group membership for all young ultracool dwarfs with parallaxes, changing the status of 23 objects (including 8 previously identified planetary-mass candidates) and fortifying the status of another 28 objects. We use our resulting age-calibrated sample to establish empirical young isochrones and show a declining frequency of VL-G objects relative to INT-G objects with increasing age. Notable individual objects in our sample include high-velocity (>~100km/s) INT-G objects, very red late-L dwarfs with high surface gravities, candidate disk-bearing members of the MBM20 cloud and {beta} Pic moving group, and very young distant interlopers. Finally, we provide a comprehensive summary of the absolute magnitudes and spectral classifications of young ultracool dwarfs, using a combined sample of 102 objects found in the field and as substellar companions to young stars.
- ID:
- ivo://CDS.VizieR/J/AJ/159/257
- Title:
- Hawaii IR parallax program. IV. L0-T8 BDs with UKIRT
- Short Name:
- J/AJ/159/257
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present parallaxes, proper motions, and J-band photometry for 348 L and T dwarfs measured using the wide-field near-infrared camera (WFCAM) on the United Kingdom Infrared Telescope (UKIRT). This is the largest single batch of infrared parallaxes for brown dwarfs to date. Our parallaxes have a median uncertainty of 3.5mas, similar to most previous ground-based infrared parallax surveys. Our target list was designed to complete a volume-limited parallax sample of L0-T8 dwarfs out to 25pc spanning declinations -30{deg} to +60{deg} (68% of the sky). We report the first parallaxes for 165 objects, and we improve on previous measurements for another 53 objects. Our targets include 104 objects (mostly early-L dwarfs) having Gaia DR2 parallax measurements with which our parallaxes are consistent. We include an extensive comparison of previous literature parallaxes for L and T dwarfs with both our results and Gaia DR2 measurements, identifying systematic offsets for some previous surveys. Our parallaxes confirm that 14 objects previously identified as wide common proper motion companions to main-sequence stars have distances consistent with companionship. We also report new J_MKO_ photometry for our targets, including the first measurements for 193 of our targets and improvements over previously published J_MKO_ photometry for another 60 targets. Altogether, our parallaxes will enable the first population studies using a volume-limited sample spanning spectral types L0-T8 defined entirely by parallaxes.
- ID:
- ivo://CDS.VizieR/III/182
- Title:
- HDE Charts: positions, proper motions
- Short Name:
- III/182
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- of Paper: The Henry Draper Extension Charts (Cannon et al., 1949), published in the form of finding charts, provide spectral classification for some 87000 stars mostly between 10th and 11th magnitude. This data, being highly valuable, as yet was practically unusable for modern computer-based astronomy. An earlier pilot project (Roeser et al. 1991) demonstrated a possibility to convert this into a star catalogue, using measurements of cartesian coordinates of stars on the charts and positions of the Astrographic Catalogue (AC) for subsequent identification. We present here a final HDEC catalogue comprising accurate positions, proper motions, magnitudes and spectral classes for 86933 stars of the Henry Draper Extension Charts.
- ID:
- ivo://CDS.VizieR/J/AJ/156/179
- Title:
- Highly r-process-enhanced field stars kinematics
- Short Name:
- J/AJ/156/179
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the kinematics of 35 highly r-process-enhanced ([Eu/Fe]>=+0.7) metal-poor (-3.8<[Fe/H]< -1.4) field stars. We calculate six-dimensional positions and velocities, evaluate energies and integrals of motion, and compute orbits for each of these stars using parallaxes and proper motions from the second Gaia data release (Cat. I/345) and published radial velocities. All of these stars have halo kinematics. Most stars (66%) remain in the inner regions of the halo (<13 kpc), and many (51%) have orbits that pass within 2.6 kpc of the Galactic center. Several stars (20%) have orbits that extend beyond 20 kpc, including one with an orbital apocenter larger than the Milky Way virial radius. We apply three clustering methods to search for structure in phase space, and we identify eight groups. No abundances are considered in the clustering process, but the [Fe/H] dispersions of the groups are smaller than would be expected by random chance. The orbital properties, clustering in phase space and metallicity, and the lack of highly r-process-enhanced stars on disk-like orbits, indicate that such stars likely were accreted from disrupted satellites. Comparison with the galaxy luminosity-metallicity relation suggests M_V_>~-9 for most of the progenitor satellites, characteristic of ultra-faint or low-luminosity classical dwarf spheroidal galaxies. Environments with low rates of star formation and Fe production, rather than the nature of the r-process site, may be key to obtaining the [Eu/Fe] ratios found in highly r-process-enhanced stars.
- ID:
- ivo://CDS.VizieR/J/AJ/159/30
- Title:
- High proper-motion M-type stars spectroscopic obs.
- Short Name:
- J/AJ/159/30
- Date:
- 11 Mar 2022
- Publisher:
- CDS
- Description:
- Large numbers of low-to-medium-resolution spectra of M-type dwarf stars from both the local Galactic disk and halo are available from various surveys. In order to fully exploit these data, we develop a template-fit method using a set of empirically assembled M dwarf/subdwarf classification templates, based on the measurements of the TiO and CaH molecular bands near 7000{AA}, which are used to classify M dwarfs/subdwarfs by spectral type and metallicity class. We further present a pipeline to automatically determine the effective temperature Teff, metallicity [M/H], {alpha}-element to iron abundance ratio [{alpha}/Fe], and surface gravity logg of M dwarfs/subdwarfs using the latest version of BT-Settl model atmospheres. We apply these methods to a set of low-to-medium-resolution spectra of 1544 high proper-motion ({mu}>=0.4"/yr) M dwarfs/subdwarfs, collected at the MDM observatory, Lick Observatory, Kitt-Peak National Observatory, and Cerro-Tololo Interamerican Observatory.
