- ID:
- ivo://CDS.VizieR/J/ApJS/241/12
- Title:
- The Asteroseismic Target List (ATL) for TESS
- Short Name:
- J/ApJS/241/12
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the target list of solar-type stars to be observed in short-cadence (2 minute) for asteroseismology by the NASA Transiting Exoplanet Survey Satellite (TESS) during its 2 year nominal survey mission. The solar-like Asteroseismic Target List (ATL) is comprised of bright, cool main-sequence and subgiant stars and forms part of the larger target list of the TESS Asteroseismic Science Consortium. The ATL uses the Gaia Data Release 2 and the Extended Hipparcos Compilation (XHIP) to derive fundamental stellar properties, to calculate detection probabilities, and to produce a rank- ordered target list. We provide a detailed description of how the ATL was produced and calculate expected yields for solar-like oscillators based on the nominal photometric performance by TESS. We also provide a publicly available source code that can be used to reproduce the ATL, thereby enabling comparisons of asteroseismic results from TESS with predictions from synthetic stellar populations.
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- ID:
- ivo://CDS.VizieR/J/MNRAS/505/5164
- Title:
- The Gaia view of the Cepheus flare
- Short Name:
- J/MNRAS/505/5164
- Date:
- 25 Oct 2021 10:05:07
- Publisher:
- CDS
- Description:
- We present a new census of candidate pre-main-sequence stars in the Cepheus flare star-forming region, based on Gaia EDR3 parallaxes, proper motions, and colour-magnitude diagrams. We identified new candidate members of the previously known young stellar groups associated with NGC 7023, L1177, L1217/L1219, L1228, L1235, and L1251. We studied the 3D structure of the star-forming complex and the distribution of tangential velocities of the young stars. The young stellar groups are located between 330 and 368pc from the Sun, divided into three kinematic subgroups, and have ages between 1 and 5 million yr. The results confirm the scenario of propagating star formation, suggested by previous studies. In addition to the bulk pre-main-sequence star population between 330 and 370pc, there is a scattered and more evolved pre-main-sequence population around 150-180pc. We found new candidate members of the nearby Cepheus Association, and identified a new moving group of 46, 15-20 million yr old pre-main-sequence stars located at a distance of 178pc, around the A0-type star HD 190833. A few pre-main-sequence stars are located at 800-900 pc, indicative of star-forming regions associated with the Galactic local arm above the Galactic latitude of +10{deg}.
- ID:
- ivo://CDS.VizieR/I/239
- Title:
- The Hipparcos and Tycho Catalogues
- Short Name:
- I/239
- Date:
- 18 Nov 2021 11:08:10
- Publisher:
- CDS
- Description:
- The Hipparcos and Tycho Catalogues are the primary products of the European Space Agency's astrometric mission, Hipparcos. The satellite, which operated for four years, returned high quality scientific data from November 1989 to March 1993. Each of the catalogues contains a large quantity of very high quality astrometric and photometric data. In addition there are associated annexes featuring variability and double/multiple star data, and solar system astrometric and photometric measurements. In the case of the Hipparcos Catalogue, the principal parts are provided in both printed and machine-readable form (on CDROM). In the case of the Tycho Catalogue, results are provided in machine-readable form only (on CDROM). Although in general only the final reduced and calibrated astrometric and photometric data are provided, some auxiliary files containing results from intermediate stages of the data processing, of relevance for the more-specialised user, have also been retained for publication. (Some, but not all, data files are available from the Centre de Donnees astronomiques de Strasbourg.) The global data analysis tasks, proceeding from nearly 1000 Gbit of raw satellite data to the final catalogues, was a lengthy and complex process, and was undertaken by the NDAC and FAST Consortia, together responsible for the production of the Hipparcos Catalogue, and the Tycho Consortium, responsible for the production of the Tycho Catalogue. A fourth scientific consortium, the INCA Consortium, was responsible for the construction of the Hipparcos observing programme, compiling the best-available data for the selected stars before launch into the Hipparcos Input Catalogue. The production of the Hipparcos and Tycho Catalogues marks the formal end of the involvement in the mission by the European Space Agency and the four scientific consortia. For more complete and detailed information on the data, the user is advised to refer to Volume 1 ("Introduction and Guide to the Data", ESA SP-1200) of the printed Hipparcos and Tycho Catalogues. The user should also note that in order to convert the Double and Multiple Systems (Component solutions) data file hip_dm_c.dat into FITS format it is first necessary to filter the file according to whether the entry is a component record (identified by COMP in field DCM5) or a correlation record (identified by CORR in field DCM5) because of the different structures of the respective records. On a Unix system this can be achieved as follows: grep COMP hip_dm_c.dat > h_dm_com.dat grep CORR hip_dm_c.dat > h_dm_cor.dat The catalogue description file (this file) gives the relevant information for converting the main data files, including h_dm_cor.dat and h_dm_com.dat, into FITS format. The machine readable data files (i.e. those available on CD-ROM and the subset available from the CDS) contain several extra fields in addition to the data from the printed catalogue. These fields are identified by the letter `M' in the data label (e.g. the field DGM1 contains data only available in the machine readable file hip_dm_g.dat).
- ID:
- ivo://CDS.VizieR/J/A+A/332/L53
- Title:
- The PL relation of galactic carbon LPVs
- Short Name:
- J/A+A/332/L53
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The estimated true parallaxes of 115 carbon LPVs and their unbiased y-values (see Sect. 4) for a study of the period-luminosity relation. The tables contains the entry in the cited Stephenson's catalogue (1989, Cat. <III/156>), the log of the period in days, the absolute magnitude in the K-band, the y-quantity as defined in Sect. 4, the difference between the estimated true parallax and the observed one, the estimated true parallax, the square root of the weight (times 100) of every used y-value for Sample 1 PL-relation (Sect. 4) and the classification into three samples (see Subsec. 3.1).
- ID:
- ivo://CDS.VizieR/J/A+A/623/A112
- Title:
- The Sco OB2 population from Gaia DR2 data
- Short Name:
- J/A+A/623/A112
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Sco OB2 association is the nearest OB association, extending over approximately 2000 square degrees on the sky. Only its brightest and most massive members are already known (from HIPPARCOS) across its entire size, while studies of its lower mass population refer only to small portions of its extent. In this work we exploit the capabilities of Gaia DR2 measurements to search for Sco OB2 members across its entire size and down to the lowest stellar masses. We used both Gaia astrometric (proper motions and parallaxes) and photometric measurements (integrated photometry and colors) to select association members, using minimal assumptions derived mostly from the HIPPARCOS studies. Gaia resolves small details in both the kinematics of individual Sco OB2 subgroups and their distribution with distance from the Sun. We developed methods to explore the 3D kinematics of a stellar population covering large sky areas. We find nearly 11000 pre-main-sequence (PMS) members of Sco OB2 (with less than 3% field-star contamination), plus ~3600 main-sequence (MS) candidate members with a larger (10-30%) field-star contamination. A higher confidence subsample of ~9200 PMS (and ~1340 MS) members is also selected (<1% contamination for the PMS), however this group is affected by larger (~15%) incompleteness. We separately classify stars in compact and diffuse populations. Most members belong to one of several kinematically distinct diffuse populations, whose ensemble clearly outlines the shape of the entire association. Upper Sco is the densest region of Sco OB2. It is characterized by a complex spatial and kinematical structure and has no global pattern of motion. Other dense subclusters are found in Lower Centaurus-Crux and in Upper Centaurus-Lupus; the richest example of the latter, which has been recently identified, is coincident with the group near V1062 Sco. Most of the clustered stars appear to be younger than the diffuse PMS population, suggesting star formation in small groups that rapidly disperse and are diluted, reaching space densities lower than field stars while keeping memory of their original kinematics. We also find that the open cluster IC 2602 has a similar dynamics to Sco OB2, and its PMS members are currently evaporating and forming a diffuse (size~10{deg}) halo around its double-peaked core.
- ID:
- ivo://CDS.VizieR/J/AJ/156/49
- Title:
- The solar neighborhood. XLIII. New nearby stars
- Short Name:
- J/AJ/156/49
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have conducted a novel search of most of the southern sky for nearby red dwarfs having low proper motions, with specific emphasis on those with {mu}<0.18"/yr, the lower cutoff of Luyten's classic proper-motion catalog. We used a tightly constrained search of the SuperCOSMOS database and a suite of photometric distance relations for photographic BRI and 2MASS JHK_s_ magnitudes to estimate distances to more than 14 million red dwarf candidates. Here we discuss 29 stars in 26 systems estimated to be within 25 pc, all of which have {mu}<0.18"/yr, that we have investigated using milliarcsecond astrometry, VRI photometry, and low-resolution spectroscopy. In total, we present the first parallaxes of 20 star systems, 9 of which are within 25 pc. We have additionally identified 14 young M dwarfs, of which 3 are new members of the nearby young moving groups, and 72 new giants, including two new carbon stars. We also present the entire catalog of 1215 sources we have identified by this means.
- ID:
- ivo://CDS.VizieR/J/AJ/154/191
- Title:
- The solar neighborhood. XLII. New nearby subdwarfs
- Short Name:
- J/AJ/154/191
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Parallaxes, proper motions, and optical photometry are presented for 51 systems consisting of 37 cool subdwarf and 14 additional high proper motion systems. Thirty-seven systems have parallaxes reported for the first time, 15 of which have proper motions of at least 1"/yr. The sample includes 22 newly identified cool subdwarfs within 100 pc, of which three are within 25 pc, and an additional five subdwarfs from 100 to 160 pc. Two systems-LSR 1610-0040 AB and LHS 440 AB-are close binaries exhibiting clear astrometric perturbations that will ultimately provide important masses for cool subdwarfs. We use the accurate parallaxes and proper motions provided here, combined with additional data from our program and others, to determine that effectively all nearby stars with tangential velocities greater than 200 km/s are subdwarfs. We compare a sample of 167 confirmed cool subdwarfs to nearby main sequence dwarfs and Pleiades members on an observational Hertzsprung-Russell diagram using M_V_ versus (V-K_s_) to map trends of age and metallicity. We find that subdwarfs are clearly separated for spectral types K5-M5, indicating that the low metallicities of subdwarfs set them apart in the H-R diagram for (V-K_s_)=3-6. We then apply the tangential velocity cutoff and the subdwarf region of the H-R diagram to stars with parallaxes from Gaia Data Release 1 and the MEarth Project to identify a total of 29 new nearby subdwarf candidates that fall clearly below the main sequence.
- ID:
- ivo://CDS.VizieR/J/AJ/155/265
- Title:
- The solar neighborhood. XLIV. RECONS discoveries
- Short Name:
- J/AJ/155/265
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe the 44 systems discovered to be within 10 pc of the Sun by the RECONS team, primarily via the long-term astrometry program at the CTIO/SMARTS 0.9 m that began in 1999. The systems-including 41 with red dwarf primaries, 2 white dwarfs, and 1 brown dwarf-have trigonometric parallaxes greater than 100 mas, with errors of 0.4-2.4 mas in all but one case. We provide updated astrometric, photometric (VRIJHK magnitudes), spectral type, and multiplicity information here. Among these are 14 systems that are new entries to the 10 pc sample, including the first parallaxes for 9 systems and new values for 5 systems that had previous parallaxes with errors greater than 10 mas or values placing them beyond 10 pc. We also provide new data for 22 systems known to lie within 10 pc and 9 systems reported to be closer than that horizon but for which new parallaxes place them further away, bringing the total to 75 systems. The 44 systems added by RECONS comprise one of every 7 systems known within 10 pc. We illustrate the evolution of the 10 pc sample from the 191 systems known when the final Yale Parallax Catalog was published in 1995 to the 317 systems known today. Even so close to the Sun, additional discoveries of white, red, and brown dwarfs are possible, both as primaries and secondaries, although we estimate that at least 90% of the stellar systems closer than 10 pc have now been identified.
- ID:
- ivo://CDS.VizieR/J/AJ/160/215
- Title:
- The solar neighborhood.XLVI. New M dwarf binaries
- Short Name:
- J/AJ/160/215
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use 20yr of astrometric data from the REsearch Consortium On Nearby Stars (RECONS) program on the Cerro Tololo Inter-American Observatory/SMARTS 0.9m telescope to provide new insight into multiple star systems in the solar neighborhood. We provide new and updated parallaxes for 210 systems and derive nine high-quality astrometric orbits with periods of 2.49-16.63yr. Using a total of 542 systems parallaxes from RECONS, we compare systems within 25pc to Gaia DR2 to define criteria for selecting unresolved astrometric multiples from the DR2 results. We find that three out of four unresolved multistar red dwarf systems within 25pc in DR2 have parallax_error >=0.32mas, astrometric_gof_al>=56, astrometric_excess-noise_sig>=108.0, ruwe>=2.0, and parallaxes more than ~10% different from the long-term RECONS results. These criteria have broad applications to any work targeting nearby stars, from studies seeking binary systems to efforts targeting single stars for planet searches.
- ID:
- ivo://CDS.VizieR/J/AJ/154/151
- Title:
- The solar neighborhood .XXXX. New young stars
- Short Name:
- J/AJ/154/151
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- As a step toward completing and characterizing the census of the solar neighborhood, we present astrometric, photometric, and spectroscopic observations of 32 systems observed with the Cerro Tololo Inter-American Observatory 0.9 m and 1.5 m telescopes. Astrometry from the 0.9 m indicates that among the 17 systems that had no previous published trigonometric parallaxes, 14 are within 25 pc. In the full sample, nine systems have proper motions larger than 0.5"/yr, including 2MASS J02511490-0352459, which exceeds 2.0"/yr. VRI photometry from the 0.9 m and optical spectra from the 1.5 m indicate that the targets have V=11-22 mag and spectral types M3.0V-L3.0V. For 2MASS J23062928-0502285 (TRAPPIST-1), we present updated astrometry and photometric variability based on over 12 years of observations. Of the nine binaries in the sample, two promise mass determinations in the next decade: LHS 6167AB, an M4.5V system for which we present an accurate parallax placing the binary at 9.7 pc, and 2MASS J23515048-2537367AB, an M8.5V system at 21.1 pc for which we present the first evidence of an unseen, low-mass companion. Most importantly, Na I and K I gravity indicators, H{alpha} measurements, long-term photometric variability, locations on the H-R diagram, and kinematic assessments indicate that as many as 13 of the systems are young, including candidate members of young moving groups, with ages less than ~120 Myr.
