- ID:
- ivo://CDS.VizieR/V/101
- Title:
- Nearest stars until 10pc
- Short Name:
- V/101
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The given catalogue is a revised version of the catalogue (Zakhozhaj, 1987). The previous numeration is preserved, and the stars, with trigonometric, photometric and spectral parallaxes >0.100" are presented. The catalogue contains data on new components of multiple visual systems, on the components of spectral-binary systems, on invisible components with masses >0.08 solar mass. New data are obtained in 90s and contained in the articles [2-6]. The catalogue contains the main characteristics of stars such as the positions, proper motions, radial velocities, parallaxes, photometrical data and also new data of masses and radii of stars. The completeness of the catalogue is about 70%.
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Search Results
- ID:
- ivo://CDS.VizieR/J/other/JDSO/15.434
- Title:
- New Binary Systems from Data of Gaia DR2
- Short Name:
- J/other/JDSO/15.
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- The author describes the discovery of 4 new pairs of stars with almost identical proper motions and parallaxes (from Gaia DR2 data).
- ID:
- ivo://CDS.VizieR/J/MNRAS/496/2021
- Title:
- New Galactic open clusters
- Short Name:
- J/MNRAS/496/2021
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of 25 new open clusters resulting from a search in dense low galactic latitude fields. We also provide, for the first time, structural and astrophysical parameters for the new findings and 34 other recently discovered open clusters using Gaia DR2 data. The candidates were confirmed by jointly inspecting the vector point diagrams and spatial distribution. The discoveries were validated by matching near known objects and comparing their mean astrometric parameters with the available literature. A decontamination algorithm was applied to the three-dimensional astrometric space to derive membership likelihoods for clusters stars. By rejecting stars with low membership likelihoods, we built decontaminated colour-magnitude diagrams and derived the clusters astrophysical parameters by isochrone fitting. The structural parameters were also derived by King-profile fittings over the stellar distributions. The investigated clusters are mainly located within 3kpc from the Sun, with ages ranging from 30Myr to 3.2Gyr and reddening limited to E(B-V)=2.5. On average, our cluster sample presents less concentrated structures than Gaia DR2 confirmed clusters, since the derived core radii are larger while the tidal radii are not significantly different. Most of them are located in the IV quadrant of the Galactic disc at low latitudes, therefore they are immersed in dense fields characteristic of the inner Milky Way.
- ID:
- ivo://CDS.VizieR/J/ApJS/150/455
- Title:
- New HIP-based parallaxes for 424 faint stars
- Short Name:
- J/ApJS/150/455
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of 424 common proper-motion companions to Hipparcos stars with good (>3{sigma}) parallaxes, thereby effectively providing new parallaxes for these companions. Compared with typical stars in the Hipparcos catalog, these stars are substantially dimmer. The catalog includes 20 white dwarfs and an additional 29 stars with M_V_>14, the great majority of the latter being M dwarfs.
- ID:
- ivo://CDS.VizieR/J/ApJS/245/32
- Title:
- Newly identified star clusters in Gaia DR2
- Short Name:
- J/ApJS/245/32
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the Star cluster Hunting Pipeline (SHiP) that can identify star clusters in Gaia second data release (DR2) data and establish a star cluster catalog for the Galactic disk. A friend-of-friend-based cluster finder method is used to identify star clusters using five-dimensional stellar parameters, l,b,{omega},{mu}_{alpha}_cos{delta}, and {mu}_{delta}_. Our new catalog contains 2443 star cluster candidates identified from disk stars located within |b|=25{deg} and with G<18mag. An automatic isochrone fitting scheme is applied to all cluster candidates. With a combination of parameters obtained from isochrone fitting, we classify cluster candidates into three classes (Class 1, 2, and 3). Class 1 clusters are the most probable star cluster candidates with the most stringent criteria. Most of these clusters are nearby (within 4kpc). Our catalog is crossmatched with three Galactic star cluster catalogs, Kharchenko+ (2013, J/A+A/558/A53), Cantat-Gaudin+ (2018, J/A+A/618/A93 and 2019, J/A+A/624/A126), and Bica+ (2019, J/AJ/157/12). The proper motion and parallax of matched star clusters are in good agreement with these earlier catalogs. We discover 76 new star cluster candidates that are not listed in these three catalogs. The majority of these are clusters older than log(age/yr)=8.0 and are located in the inner disk with |b|<5{deg}. The recent discovery of new star clusters suggests that current Galactic star cluster catalogs are still incomplete. Among the Class 1 cluster candidates, we find 56 candidates for star cluster groups.
- ID:
- ivo://CDS.VizieR/J/MNRAS/502/6080
- Title:
- New members of Cygnus OB2 from Gaia DR2
- Short Name:
- J/MNRAS/502/6080
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Due to the high quality of Gaia DR2 stellar parallaxes and proper motions, we can study the Cygnus OB2 region up to G=17.5mag in circular region centred at (l,b)=(79.8{deg},+0.8{deg}) of radius 1{deg}. We detect four over-densities in the Vector Point Diagram. We apply a parametric model of the proper motion distribution and determine their mean proper motions, identify their members and estimate their distances by analyzing the parallaxes of the most probable members. We confirm that one of these regions is Cygnus OB2, whose mean proper motion is (pmRA*cosDE,pmDE)=(-2.71+/-0.02,-4.24+/-0.02)mas/yr. We identify 2767 astrometric members at an estimated distance of 1683 {+/-} 5 pc. A detailed comparison of these members with 333 photometric and spectroscopic Cygnus OB2 members shows that 33 stars of the last group are not members, 16 of them are O-B stars. 300 members in common lead to estimate a distance to the association of 1669+/-6pc. One of the remaining over-densities is the open cluster UCB585 for which we find eight more members, located at ~1460pc. The other two groups count 179 and 188 proper motion members which are distributed throughout the region and situated at a distance of ~1280 pc. The estimated distances of these four groups suggest the existence of different substructures in the Cygnus OB2 region along the line of sight.
- ID:
- ivo://CDS.VizieR/J/A+A/635/A45
- Title:
- 570 new open clusters in the Galactic disc
- Short Name:
- J/A+A/635/A45
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Open clusters are key targets for studies of Galaxy structure and evolution, and stellar physics. Since the Gaia data release 2 (DR2), the discovery of undetected clusters has shown that previous surveys were incomplete. Our aim is to exploit the Big Data capabilities of machine learning to detect new open clusters in Gaia DR2, and to complete the open cluster sample to enable further studies of the Galactic disc. We use a machine-learning based methodology to systematically search the Galactic disc for overdensities in the astrometric space and identify the open clusters using photometric information. First, we used an unsupervised clustering algorithm, DBSCAN, to blindly search for these overdensities in Gaia DR2 (l, b, varpi, mu_alpha_*, mu_delta_), then we used a deep learning artificial neural network trained on colour-magnitude diagrams to identify isochrone patterns in these overdensities, and to confirm them as open clusters. We find 570 new open clusters distributed along the Galactic disc in the region |b|<20{deg}. We detect substructure in complex regions, and identify the tidal tails of a disrupting cluster UBC 274 of ~3Gyr located at ~2kpc. Adapting the mentioned methodology to a Big Data environment allows us to target the search using the physical properties of open clusters instead of being driven by computational limitations. This blind search for open clusters in the Galactic disc increases the number of known open clusters by 45%.
- ID:
- ivo://CDS.VizieR/J/PAZh/34/21
- Title:
- New spectral types for Tycho2 stars
- Short Name:
- J/PAZh/34/21
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We compare the spectroscopic and trigonometric parallaxes of common stars from the Tycho-2 Spectral Type and Hipparcos Catalogues. This comparison has revealed that the distance estimations for the overwhelming majority of stars by both methods yield very similar results. However, there is a small fraction of stars for which the distance estimates differences.
- ID:
- ivo://CDS.VizieR/J/ApJ/867/79
- Title:
- NIR observations of GF 9/LDN 1082C field stars
- Short Name:
- J/ApJ/867/79
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The orientation of the magnetic field (B field) in the filamentary dark cloud GF 9 was traced from the periphery of the cloud into the L1082C dense core that contains the low-mass, low-luminosity Class 0 young stellar object (YSO) GF 9-2 (IRAS 20503+6006). This was done using SOFIA HAWC+ dust thermal emission polarimetry (TEP) at 216{mu}m in combination with Mimir near-infrared background starlight polarimetry (BSP) conducted in the H band (1.6{mu}m) and K band (2.2{mu}m). These observations were augmented with published I-band (0.77{mu}m) BSP and Planck 850{mu}m TEP to probe B-field orientations with offset from the YSO in a range spanning 6000au to 3pc. No strong B-field orientation change with offset was found, indicating remarkable uniformity of the B-field from the cloud edge to the YSO environs. This finding disagrees with weak-field models of cloud core and YSO formation. The continuity of inferred B-field orientations for both TEP and BSP probes is strong evidence that both are sampling a common B field that uniformly threads the cloud, core, and YSO region. Bayesian analysis of Gaia DR2 stars matched to the Mimir BSP stars finds a distance to GF 9 of 270+/-10pc. No strong wavelength dependence of B-field orientation angle was found, contrary to previous claims.
- ID:
- ivo://CDS.VizieR/J/ApJS/239/26
- Title:
- NOFS astrometric measurements for distant WDs
- Short Name:
- J/ApJS/239/26
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper presents new trigonometric parallaxes and proper motions for 214 stars. The measurements were made at the US Naval Observatory Flagstaff Station between 1989 and 2017, and the average uncertainty in the parallax values is 0.6mas. We find good agreement with Gaia Data Release 2 measurements for the stars in common, although there may be a small systematic offset similar to what has been found by other investigators. The sample is matched to catalogs and the literature to create a photometric data set that spans the ultraviolet to the mid-infrared. New mid-infrared photometry is obtained for 19 stars from archived Spitzer mosaics. New optical spectroscopy is presented for seven systems and additional spectra were obtained from the literature. We identify a subsample of 179 white dwarfs (WDs) at distances of 25-200pc. Their spectral energy distributions (SEDs) are analyzed using model atmospheres. The models reproduce the entire flux-calibrated SED very well and provide the atmospheric chemical composition, temperature, surface gravity, mass, and cooling age of each WD. Twenty-six WDs are newly classified, and 12 systems are presented as candidate unresolved binaries. We confirm one WD+red dwarf system and identify two WDs as candidate dust disk systems. Twelve old and high-velocity systems are identified as candidate thick disk or halo objects. The WDs in the sample generally have Galactic disk-like ages of <8Gyr and masses close to the canonical 0.6M_{sun}_.
