- ID:
- ivo://CDS.VizieR/J/MNRAS/504/356
- Title:
- Updated parameters of 1743 open clusters
- Short Name:
- J/MNRAS/504/356
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this study, we follow up our recent paper (Monteiro et al., )2020MNRAS.499.1874M and present a homogeneous sample of fundamental parameters of open clusters in our Galaxy, entirely based on Gaia DR2 data. We used published membership probability of the stars derived from Gaia DR2 data and applied our isochrone fitting code, updated as in Monteiro et al. (2020MNRAS.499.1874M), to G_BP_ and G_RP_Gaia DR2 data for member stars. In doing this, we take into account the nominal errors in the data and derive distance, age, and extinction of each cluster. This work therefore provides parameters for 1743 open clusters and, as a by-product, a list of likely not physical or dubious open clusters is provided as well for future investigations. Furthermore, it was possible to estimate the mean radial velocity of 831 clusters (198 of which are new and unpublished so far), using stellar radial velocities from Gaia DR2 catalogue. By comparing the open cluster distances obtained from isochrone fitting with those obtained from a maximum likelihood estimate of individual member parallaxes, we found a systematic offset of (-0.05 {\pm} 0.04) mas.
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- ID:
- ivo://CDS.VizieR/J/other/NatAs/6.89
- Title:
- Upper Scorpius members
- Short Name:
- J/other/NatAs/6.
- Date:
- 03 Mar 2022 16:55:14
- Publisher:
- CDS
- Description:
- The nature and origin of free-floating planets (FFPs) are still largely unconstrained because of a lack of large homogeneous samples to enable a statistical analysis of their properties. So far, most FFPs have been discovered using indirect methods; microlensing surveys have proved particularly successful to detect these objects down to a few Earth masses. However, the ephemeral nature of microlensing events prevents any follow-up observations and individual characterization. Several studies have identified FFPs in young stellar clusters and the Galactic field but their samples are small or heterogeneous in age and origin. Here we report the discovery of between 70 and 170 FFPs (depending on the assumed age) in the region encompassing Upper Scorpius and Ophiuchus, the closest young OB association to the Sun. We found an excess of FFPs by a factor of up to seven compared with core-collapse model predictions, demonstrating that other formation mechanisms may be at work. We estimate that ejection from planetary systems might have a contribution comparable to that of core collapse in the formation of FFPs. Therefore, ejections due to dynamical instabilities in giant exoplanet systems must be frequent within the first 10Myr of a system's life.
- ID:
- ivo://CDS.VizieR/J/AJ/160/44
- Title:
- Upper Scorpius spectroscopy and photometry
- Short Name:
- J/AJ/160/44
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have refined the census of stars and brown dwarfs in the Upper Sco association (~10Myr, ~145pc) by (1) updating the selection of candidate members from our previous survey to include the high-precision astrometry from the second data release of Gaia, (2) obtaining spectra of a few hundred candidate members to measure their spectral types and verify their youth, and (3) assessing the membership (largely with Gaia astrometry) of 2020 stars toward Upper Sco that show evidence of youth in this work and previous studies. We arrive at a catalog of 1761 objects that are adopted as members of Upper Sco. The distribution of spectral types among the adopted members is similar to those in other nearby star-forming regions, indicating a similar initial mass function. In previous studies, we have compiled mid-infrared photometry from the Wide-field Infrared Survey Explorer and the Spitzer Space Telescope for members of Upper Sco and used those data to identify the stars that show evidence of circumstellar disks; we present the same analysis for our new catalog of members. As in earlier work, we find that the fraction of members with disks increases with lower stellar masses, ranging from <~10% for >1M{sun} to ~22% for 0.01-0.3M{sun}. Finally, we have estimated the relative ages of Upper Sco and other young associations using their sequences of low-mass stars in M_G_RP__ versus G_BP_-G_RP_. This comparison indicates that Upper Sco is a factor of two younger than the {beta}Pic association (21-24Myr) according to both nonmagnetic and magnetic evolutionary models.
- ID:
- ivo://CDS.VizieR/I/333
- Title:
- URAT Parallax Catalog (UPC)
- Short Name:
- I/333
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The URAT Parallax Catalog (UPC) consists of 112177 parallaxes. The catalog utilizes all Northern Hemisphere epoch data from the United States Naval Observatory (USNO) Robotic Astrometric Telescope (URAT). This data includes all individual exposures from April 2012 to June 2015 giving a larger epoch baseline for determining parallaxes over the 2-year span of the First USNO Robotic Astrometric Telescope Catalog (URAT1) (Zacharias et al., 2015, Cat. I/329) published data. The URAT parallax pipeline is custom code that utilizes routines from (Jao, C.-W., 2004, PhD thesis Georgia Stat), the JPL DE405 ephemeris and Green's parallax factor (Green, R.M., 1985, Spherical Astronomy) for determining parallaxes from a weighted least-squares reduction. The relative parallaxes have been corrected to absolute by using the distance color relation described in (Finch et. al, 2014, Cat. J/AJ/148/119) to determine a mean distance of all UCAC4 reference stars (R=8-16 mag) used in the astrometric reductions. Presented here are all significant parallaxes from the URAT Northern Hemisphere epoch data comprising of 2 groups: a) URAT parallax results for stars with prior published parallax, and b) first time trigonometric parallaxes as obtained from URAT data of stars without prior published parallax. Note, more stringent selection criteria have been applied to the second group than the first in order to keep the rate of false detections low. For specific information about the astrometric reductions please see 'The First U.S. Naval Observatory Robotic Astrometric Telescope Catalog' published paper (Zacharias et al., 2015AJ....150..101Z, Cat. I/329). For complete details regarding the parallax pipeline please see 'Parallax Results From URAT Epoch Data' (Finch and Zacharias, 2016, AJ, in press). This catalog gives all positions on the ICRS at Epoch J2014.0; it covers the magnitude range 6.56 to 16.93 in the URAT band-pass, with an average parallax precision of 4.3mas for stars having no known parallax and 10.8mas for stars matched to external parallax sources. This catalog covers the sky from about North of -12.75{deg} declination. This catalog was matched with the Hipparcos catalog, Yale Parallax Catalog, (Finch & Zacharias, 2016, AJ, in press), MEarth (Dittmann et. al., 2014ApJ...784..156D) and the SIMBAD database to obtain known parallax and star names. For stars matched to SIMBAD using the automated search feature, only the parallaxes are given so no information on the parallax errors or source for the parallax are reported for those stars in this catalog. A flag is included to show which catalog or database the URAT parallax was matched with. Only the data from the first catalog that was matched is reported here according to the following priority list. This means for example, if a star was matched with Hipparcos, that information was used while possible other catalog data are not listed here. -------------------------------------------------------- # stars flg catalog -------------------------------------------------------- 53500 0 no catalog match 55549 1 Hipparcos 254 2 Yale Parallax Catalog 1041 3 Finch and Zacharias 2016 (UPM NNNN-NNNN) 1431 4 MEarth parallaxes 402 5 SIMBAD Database (w/parallax) -------------------------------------------------------- 112177 total number stars in catalog -------------------------------------------------------- Not all parallaxes from the URAT epoch data are included in this catalog. Only those data meeting the following criteria have been included. For the epoch data we only used data having a FWHM<=7.0pixel; amplitude between 500 and 30000ADU; sigma x,y <=90.0mas; number of observations >=20 and epoch span>=1.0 years. The limits imposed on individual image amplitude, image profile width (FWHM) and position fit errors (sigma) are set to not allow saturated stars, stars with too few photons or poorly determined positions to be used in the parallax solution. We present all URAT parallax solutions having a known parallax from an external data source regardless of the quality of the solution (srcflg=1-5). This was done for the user to better understand the limitations for determining parallaxes with the current URAT epoch data. For the remaining URAT parallaxes without a match to any published trigonometric parallax (srcflg=0) we only present a parallax solutions having: 1) a parallax error <=10mas 2) a parallax error <=1/4 the relative parallax 3) epoch span >=1.5 years 4) number of observations used >=30 5) fit sigma<=1.4 (unit weight) 6) average image elongation <1.1. All of these cuts have been implemented in an attempt to lower the number of possible erroneous parallax solutions entering our catalog. However, the URAT reduction process does not take provisions for close doubles (blended images) of arcsecond-level separations. Many of the parallaxes, particularly those with large mean elongation, large parallax error, large fit sigma and many rejected observations are possibly blended images leading to a higher chance of an erroneous parallax solutions. A visual inspection of all residual plots and real sky images would not be practical for the entire catalog. However, we have included information in the catalog to help the user to determine if a solution should be investigated further.
- ID:
- ivo://CDS.VizieR/J/AJ/103/638
- Title:
- USNO Photographic Parallaxes. I.
- Short Name:
- J/AJ/103/638
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The U.S. Naval Observatory CCD trigonometric parallax program is described in detail, including the instrumentation employed, observing procedures followed, and reduction procedures applied. Astrometric results are presented for 72 stars ranging in apparent brightness from V=15.16 to 19.58. Photometry (V and V-I on the Kron-Cousins system) is presented for the parallax stars and for all 426 individual reference stars employed in the astrometric solutions. Corrections for differential color refraction, calibrated to the observed V-I colors, have been applied to all astrometric measures. The mean errors in the relative parallaxes range from +/-0.0005" to +/-0.0027" with a median value of +/-0.0010". Seventeen of the 23 stars with V_tan_>200km/s form a well-delineated sequence of extreme subdwarfs covering 11.5<M_V_<14.5 in the M_V_ vs V-I diagram. The transformation to the M_bol_ vs log T_eff_ plane is presented and the results are compared with various model interior computations. Within the limitations due to the uncertain T_eff_ scale for cool dwarfs and subdwarfs, the coolest members of the extreme subdwarf sequence appear to be near the hydrogen-burning minimum mass limit for stars with metallicities of [M/H]~-2.
- ID:
- ivo://CDS.VizieR/J/AJ/105/1571
- Title:
- USNO Photographic Parallaxes IX
- Short Name:
- J/AJ/105/1571
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Trigonometric parallaxes, relative proper motions, and photometry are presented for 122 stars in 111 systems. Of these stars, 70 are brighter than V = 10.0.
- ID:
- ivo://CDS.VizieR/J/AJ/155/39
- Title:
- Variability properties of TIC sources with KELT
- Short Name:
- J/AJ/155/39
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Kilodegree Extremely Little Telescope (KELT) has been surveying more than 70% of the celestial sphere for nearly a decade. While the primary science goal of the survey is the discovery of transiting, large-radii planets around bright host stars, the survey has collected more than 10^6^ images, with a typical cadence between 10-30 minutes, for more than four million sources with apparent visual magnitudes in the approximate range 7<V<13. Here, we provide a catalog of 52741 objects showing significant large-amplitude fluctuations likely caused by stellar variability, as well as 62229 objects identified with likely stellar rotation periods. The detected variability ranges in rms-amplitude from ~3 mmag to ~2.3 mag, and the detected periods range from ~0.1 to >~2000 days. We provide variability upper limits for all other ~4000000 sources. These upper limits are principally a function of stellar brightness, but we achieve typical 1{sigma} sensitivity on 30 min timescales down to ~5 mmag at V~8, and down to ~43 mmag at V~13. We have matched our catalog to the TESS Input catalog and the AAVSO Variable Star Index to precipitate the follow-up and classification of each source. The catalog is maintained as a living database on the Filtergraph visualization portal at the URL https://filtergraph.com/kelt_vars.
- ID:
- ivo://CDS.VizieR/J/A+A/512/A37
- Title:
- Velocities of 43 nearby L dwarfs
- Short Name:
- J/A+A/512/A37
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present radial velocity measurements of a sample of L0-L8 dwarfs observed with VLT/UVES and Keck/HIRES. We combine these measurements with distance and proper motion from the literature to determine space motions for 43 of our targets. We identify nine candidate members of young moving groups, which have ages of 50-600Myr according to their space motion.
- ID:
- ivo://CDS.VizieR/II/364
- Title:
- VIRAC. The VVV Infrared Astrometric Catalogue
- Short Name:
- II/364
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present VIRAC version 1, a near-infrared proper motion and parallax catalogue of the VISTA Variables in the Via Lactea (VVV) survey for 312587642 unique sources averaged across all overlapping pawprint and tile images covering 560deg^2^ of the bulge of the Milky Way and southern disc. The catalogue includes 119 million high-quality proper motion measurements, of which 47 million have statistical uncertainties below 1mas/yr. In the 11<K_s_<14 magnitude range, the high-quality motions have a median uncertainty of 0.67mas/yr. The catalogue also includes 6935 sources with quality-controlled 5{sigma} parallaxes with a median uncertainty of 1.1mas. The parallaxes show reasonable agreement with the Tycho-Gaia Astrometric Solution, though caution is advised for data with modest significance. The SQL data base housing the data is made available via the web. We give example applications for studies of Galactic structure, nearby objects (low-mass stars and brown dwarfs, subdwarfs, white dwarfs) and kinematic distance measurements of young stellar objects. Nearby objects discovered include LTT 7251 B, an L7 benchmark companion to a G dwarf with over 20 published elemental abundances, a bright L subdwarf, VVV 1256-6202, with extremely blue colours and nine new members of the 25pc sample. We also demonstrate why this catalogue remains useful in the era of Gaia. Future versions will be based on profile fitting photometry, use the Gaia absolute reference frame and incorporate the longer time baseline of the VVV extended survey.
- ID:
- ivo://CDS.VizieR/J/A+A/341/121
- Title:
- Visual binary orbits and masses
- Short Name:
- J/A+A/341/121
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The paper gives orbits and masses for some 200 nearby visual binaries, as derived from combining ground-based and Hipparcos data. Table 6 gives identifications and notes, and points to the detailed data in Table 1 (short-P systems with mass-ratio from the Hipparcos observations), Table 3 (mass-uncertainty below 10%) or Table 4 (mass-uncertainty above 10%).
