- ID:
- ivo://CDS.VizieR/J/A+A/627/A4
- Title:
- Praesepe (NGC 2632) and its tidal tails
- Short Name:
- J/A+A/627/A4
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Within a 400pc sphere around the Sun, we search for Praesepe's tidal tails in the Gaia Data Release 2 (DR2) data set. We used a modified convergent-point method to find stars with space velocities close to the space velocity of the Praesepe cluster. We find a clear indication for the existence of Praesepe's tidal tails, both extending up to 165pc from the centre of the cluster. A total of 1393 stars populate the cluster and its tails, giving a total mass of 794M_{sun}_. We determined a tidal radius of 10.77pc for the cluster and a tidal mass of 483M_{sun}_. The corresponding half-mass radius is 4.8pc. We also found a clear indication for mass segregation in the cluster. The tidal tails outside 2 tidal radii are populated by 389 stars. The total contamination of our sample by field stars lies between 50 and 100 stars or 3.6-7.2%. We used an astrometrically and photometrically clean subsample of Gaia DR2, which makes our Praesepe sample incomplete beyond M~12.0mag; this corresponds to about 0.25M_{sun}_. A comparison with an N-body model of the cluster and its tails shows remarkably good coincidence. Three new white dwarfs are found in the tails.
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Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/156/142
- Title:
- Precision cluster abund. for APOGEE using SDSS DR14
- Short Name:
- J/AJ/156/142
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Open Cluster Chemical Abundances and Mapping (OCCAM) survey aims to produce a comprehensive, uniform, infrared-based spectroscopic data set for hundreds of open clusters, and to constrain key Galactic dynamical and chemical parameters from this sample. This second contribution from the OCCAM survey presents analysis of 259 member stars with [Fe/H] determinations in 19 open clusters, using Sloan Digital Sky Survey Data Release 14 (SDSS/DR14) data from the Apache Point Observatory Galactic Evolution Experiment and ESA Gaia. This analysis, which includes clusters with R_GC_ ranging from 7 to 13 kpc, measures an [Fe/H] gradient of -0.061+/-0.004 dex/kpc. We also confirm evidence of a significant positive gradient in the {alpha}-elements ([O/Fe], [Mg/Fe], and [Si/Fe]) and present evidence for a significant negative gradient in iron-peak elements ([Mn/Fe] and [Ni/Fe]).
- ID:
- ivo://CDS.VizieR/J/MNRAS/347/101
- Title:
- Precision colour-magnitude diagram of M67
- Short Name:
- J/MNRAS/347/101
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have calibrated and combined an extensive set of BVI observations of M67 to produce a colour-magnitude diagram of stars measured with high relative precision. We have selected stars that are most likely to be single-star members of the cluster using proper motion, radial velocity, and variability information from the literature, and an examination of the most probable colour-magnitude diagram locations of unresolved stellar blends. We have made detailed comparisons of our photometry of the selected stars with theoretical models, and discuss the most notable discrepancies. Observations of M67 turn-off stars are a severe test of algorithms attempting to describe convective cores in the limit of small extent, and we find strong evidence of a 'hook' just fainter than the turn-off gap. The stars in M67 support assertions that the degree of convective core overshooting decreases to zero for stars with masses in the range 1.0<(M/M_{sun}_)<=1.5, but that the degree of overshoot is smaller than currently used in published isochrones. We also verify that all current theoretical models for the lower main sequence (with the exception of Baraffe et al., 1998, Cat. J/A+A/337/403) are too blue for MV>~6, even when the sequences are shifted to match M67 near the MV of the Sun, probably due to a combination of problems with colour-Teff transformations and realistic surface boundary conditions for models. Finally, we identify a subset of cluster members with unusual photometry (candidate red giant binaries, blue straggler stars, and triple systems) deserving of further study.
- ID:
- ivo://CDS.VizieR/J/MNRAS/424/3178
- Title:
- Pre-main-sequence isochrones. Pleiades benchmark
- Short Name:
- J/MNRAS/424/3178
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a critical assessment of commonly used pre-main-sequence isochrones by comparing their predictions to a set of well-calibrated colour-magnitude diagrams of the Pleiades in the wavelength range 0.4-2.5um. Our analysis shows that for temperatures less than 4000K, the models systematically overestimate the flux by a factor of 2 at 0.5um, though this decreases with wavelength, becoming negligible at 2.2um. In optical colours this will result in the ages for stars younger than 10Myr being underestimated by factors of between 2 and 3. We show that using observations of standard stars to transform the data into a standard system can introduce significant errors in the positioning of pre-main sequences in colour-magnitude diagrams. Therefore, we have compared the models to the data in the natural photometric system in which the observations were taken. Thus we have constructed and tested a model of the system responses for the Wide-Field Camera on the Isaac Newton Telescope. As a benchmark test for the development of pre-main-sequence models, we provide both our system responses and the Pleiades sequence.
- ID:
- ivo://CDS.VizieR/J/A+A/615/A148
- Title:
- Pre-main sequence stars in Scorpius OB1
- Short Name:
- J/A+A/615/A148
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The low-mass members of OB associations, expected to be a major component of their total population, are in most cases poorly studied because of the difficulty of selecting these faint stars in crowded sky regions. Our knowledge of many OB associations relies on only a relatively small number of massive members. We study here the Sco OB1 association, with the aim of a better characterization of its properties, such as global size and shape, member clusters and their morphology, age and formation history, and total mass. We use deep optical and near-infrared (NIR) photometry from the VPHAS+ and VVV surveys, over a wide area (2.6{deg}x2.6{deg}), complemented by Spitzer infrared (IR) data, and Chandra and XMM-Newton X-ray data. A new technique is developed to find clusters of pre-main sequence M-type stars using suitable color-color diagrams, complementing existing selection techniques using narrow-band H{alpha} photometry or NIR and ultraviolet (UV) excesses, and X-ray data. We find a large population of approximately 4000 candidate low-mass Sco OB1 members whose spatial properties correlate well with those of H{alpha}-emission, NIR-excess, UV-excess, and X-ray detected members, and unresolved X-ray emission. The low-mass population is spread among several interconnected subgroups: they coincide with the HII regions G345.45+1.50 and IC4628, and the rich clusters NGC 6231 and Trumpler 24, with an additional subcluster intermediate between these two. The total mass of Sco OB1 is estimated to be ~8500M_{sun}_. Indication of a sequence of star-formation events is found, from South (NGC 6231) to North (G345.45+1.50). We suggest that the diluted appearance of Trumpler 24 indicates that the cluster is now dissolving into the field, and that tidal stripping by NGC 6231 nearby contributes to the process.
- ID:
- ivo://CDS.VizieR/J/ApJS/209/32
- Title:
- Probable young stars in the MYStIX project
- Short Name:
- J/ApJS/209/32
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Massive Young star-forming complex Study in Infrared and X-rays (MYStIX) project requires samples of young stars that are likely members of 20 nearby Galactic massive star-forming regions. Membership is inferred from statistical classification of X-ray sources, from detection of a robust infrared excess that is best explained by circumstellar dust in a disk or infalling envelope and from published spectral types that are unlikely to be found among field stars. We present the MYStIX membership lists here, and describe in detail the statistical classification of X-ray sources via a "Naive Bayes Classifier."
- ID:
- ivo://CDS.VizieR/J/A+A/451/901
- Title:
- Proper motion and BV photometry in Trumpler 2
- Short Name:
- J/A+A/451/901
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of a complex study of the galactic open cluster Trumpler 2 are presented. In order to obtain the proper motions, the positions of approximately 3000 stars up to the limit magnitude B~16.25mag in the area 80'x80' around the cluster were measured on 6 plates with a maximal epoch difference of 63-years. The root-mean error of the relative proper motions is 4.2mas/yr. The catalogue of BV magnitudes of all the stars in the investigated area was compiled. The selection of the cluster members within the region of R<16 arcmin from the center of the cluster was made. Altogether, 148 stars were considered to be cluster members by both astrometrical and photometrical criteria. We present the estimated age (8.91E+07) and physical parameters of the cluster and append the catalogues of the proper motions and of the photometry of the stars.
778. Proper motion in M34
- ID:
- ivo://CDS.VizieR/J/AJ/111/1193
- Title:
- Proper motion in M34
- Short Name:
- J/AJ/111/1193
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have measured proper motions, positions, magnitudes, and colors for 630 stars to V~16.2 in the vicinity of the open cluster NGC 1039=M34. A proper motion membership probability analysis has been performed. We give for all stars the equatorial coordinates, the proper motions, the V magnitude, and the membership probability. For the most likely cluster members we also give B-V and (V-I)K colors. Cross identifications with previous surveys are also provided. We find an age for the cluster of 200-250Myr and a distance of 475parsecs.
- ID:
- ivo://CDS.VizieR/J/A+A/396/125
- Title:
- Proper motions and BV photometry in NGC 1513
- Short Name:
- J/A+A/396/125
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of astrometric and photometric investigations of the poorly studied open cluster NGC 1513 are presented. The proper motions of 333 stars with a root-mean-square error of 1.9mas/yr were obtained by means of the automated measuring complex "Fantasy". Eight astrometric plates covering the time interval of 101 years were measured and a total of 141 astrometric cluster members identified. BV CCD-photometry was obtained for stars in an area 17'x17' centered on the cluster. Altogether 33 stars with high reliability were considered to be cluster members by two criteria. The estimated age of NGC 1513 is 2.54E+08 years.
- ID:
- ivo://CDS.VizieR/J/MNRAS/389/285
- Title:
- Proper motions and JHK of 24 Berkeley clusters
- Short Name:
- J/MNRAS/389/285
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The main astrophysical parameters of 24 previously unstudied open clusters of Berkeley catalogue are presented here. JHK near-infrared (Two Micron All Sky Survey, Cat. II/246) photometry and the proper motions astrometry of Naval Observatory Merged Astrometric Dataset (NOMAD, Cat. I/297) are used. The clusters' centres, angular diameters, ages, distances and colour excesses for these clusters are estimated for the first time.
