- ID:
- ivo://CDS.VizieR/J/AcA/59/349
- Title:
- NGC 1502 UBVIc photometry
- Short Name:
- J/AcA/59/349
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results of variability search in the field of the young open cluster NGC 1502. Eight variable stars were discovered. Of six other stars in the observed field that were suspected for variability, we confirm variability of two, including one beta Cep star, NGC 1502-26. The remaining four suspects were found to be constant in our photometry. In addition, UBVIc photometry of the well-known massive eclipsing binary SZ Cam was obtained.
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Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/115/734
- Title:
- NGC 6231 UBVRI and H{alpha} photometry
- Short Name:
- J/AJ/115/734
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- UBVRI and H{alpha} CCD photometry has been obtained for the young open cluster NGC 6231. From the R-H{alpha} color, a measure of the H{alpha} emission, we find 12 pre-main-sequence (PMS) members and seven possible PMS members in the cluster. Applying recent stellar evolutionary tracks and PMS evolutionary tracks, we derive the age, age spread, and initial mass function of the cluster. The initial mass function of NGC 6231 is a Gaussian with a turnover at logm~0.4 (m~2.5M_{Sun}_) and shows an abrupt decrease in the number of low-mass stars. Possible reasons for the suppression of low-mass star formation and star formation processes are discussed.
- ID:
- ivo://CDS.VizieR/J/MNRAS/453/1095
- Title:
- NGC 6866 UBVRI photometry
- Short Name:
- J/MNRAS/453/1095
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present CCD UBVRI photometry of the field of the open cluster NGC 6866. Structural parameters of the cluster are determined utilizing the stellar density profile of the stars in the field. We calculate the probabilities of the stars being physical members of the cluster, using their astrometric data, and perform further analyses using only the most probable members. The reddening and metallicity of the cluster were determined by independent methods. The LAMOST spectra and the ultraviolet excess of the F- and G-type main-sequence stars in the cluster indicate that the metallicity of the cluster is about the solar value. We estimated the reddening E(B-V)=0.074+/-0.050mag using the U-B versus B-V two-colour diagram. The distance modula, the distance and the age of NGC 6866 were derived as {mu}=10.60+/-0.10mag, d=1189+/-75pc and t=813+/-50Myr, respectively, by fitting colour-magnitude diagrams of the cluster with the PARSEC isochrones. The Galactic orbit of NGC 6866 indicates that the cluster is orbiting in a slightly eccentric orbit with e=0.12. The mass function slope x=1.35+/-0.08 was derived by using the most probable members of the cluster.
- ID:
- ivo://CDS.VizieR/J/A+A/616/A124
- Title:
- NGC 3105 UBVR photometry
- Short Name:
- J/A+A/616/A124
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- NGC 3105 is a young open cluster hosting blue, yellow, and red supergiants. This rare combination makes it an excellent laboratory for constraining evolutionary models of high-mass stars. It has been poorly studied, and the fundamental parameters such as its age or distance are not well defined. We intend to characterise in an accurate way the cluster and its evolved stars, for which we derive for the first time atmospheric parameters and chemical abundances. We performed a complete analysis combining UBVR photometry with spectroscopy. We obtained spectra with classification purposes for 14 blue stars and high-resolution spectroscopy for an in-depth analysis of the six other evolved stars. We identify 126 B-type likely members within a radius of 2.7+/-0.6arcmin, which implies an initial mass, Mcl~=4100M_{sun}_. We find a distance of 7.2+/-0.7kpc for NGC 3105, placing it at R_GC_=10.0+/-1.2kpc. Isochrone fitting supports an age of 28+/-6Ma, implying masses around 9.5M_{aun}_ for the supergiants. A high fraction of Be stars (~25%) is found at the top of the main sequence down to spectral type b3. From the spectral analysis we estimate for the cluster an average v_rad_=+46.9+/-0.9km/s and a low metallicity, [Fe/H]=-0.29+/-0.22. We also have determined, for the first time, chemical abundances for Li, O, Na, Mg, Si, Ca, Ti, Ni, Rb, Y, and Ba for the evolved stars. The chemical composition of the cluster is consistent with that of the Galactic thin disc. An overabundance of Ba is found, supporting the enhanced s-process. NGC 3105 has a low metallicity for its Galactocentric distance, comparable to typical LMC stars. It is a valuable spiral tracer in a very distant region of the Carina-Sagittarius spiral arm, a poorly known part of the Galaxy. As one of the few Galactic clusters containing blue, yellow, and red supergiants, it is massive enough to serve as a test bed for theoretical evolutionary models close to the boundary between intermediate- and high-mass stars.
- ID:
- ivo://CDS.VizieR/J/MNRAS/419/2379
- Title:
- NGC 6866 variables V and I light curves
- Short Name:
- J/MNRAS/419/2379
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results of a variability search in the intermediate-age open cluster NGC 6866 from 29 nights over two observing seasons. We find 28 periodic variables, of which 19 are newly identified. The periods of these variables, which have V magnitudes from 11.5 to 19.3mag, range from ~48min to 37d. We detected several {delta} Scuti stars, some of which are of high amplitude, as well as {gamma} Doradus and rotational variables, and eclipsing binaries. In order to study the physical properties of the cluster, we obtained UBVRI photometry of all the stars on a good photometric night. The radial distribution of the stellar surface density shows that the cluster has a radial extent of about 7-arcmin ( ~3pc) with a peak density of 5.7+/-0.7stars/arcmin^2^ at the cluster centre. The colour-colour diagram indicates a reddening of E(B-V)=0.10mag towards NGC 6866. A distance of ~1.47kpc and an age of ~630Myr are estimated from the colour-magnitude diagram using the theoretical isochrones of solar metallicity.
146. OGLE SMC clusters
- ID:
- ivo://CDS.VizieR/J/AcA/48/175
- Title:
- OGLE SMC clusters
- Short Name:
- J/AcA/48/175
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the catalog of clusters found in the area of ~2.4 square degrees in the central region of the Small Magellanic Cloud. The catalog contains data for 238 clusters, 72 of them are new objects. For each cluster equatorial coordinates, radii, approximate number of members, cross-identification, finding chart and color magnitude diagrams: V-(B-V) and V-(V-I) are provided.
- ID:
- ivo://CDS.VizieR/J/MNRAS/470/4285
- Title:
- Open cluster King 1 photometry
- Short Name:
- J/MNRAS/470/4285
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyse the poorly studied open cluster King 1 in the second Galactic quadrant. From wide-field photometry, we have studied the spatial distribution of this cluster. We determined that the centre of King 1 is located at {alpha}_2000_=00:22 and {delta}_2000_=+64:23. By parameterizing the stellar density with a King profile, we have obtained a central density of {rho}_0_= 6.5+/-0.2star/arcmin^2^ and a core radius of r_core_=1.9+/-0.2arcmin. By comparing the observed colour-magnitude diagram of King 1 with those of similar open clusters and with different sets of isochrones, we have estimated an age of 2.8+/-0.3Gyr, a distance modulus of (m-M)_o_=10.6+/-0.1mag and a reddening of E(B-V)=0.80+/-0.05mag. To complete our analysis, we acquired medium resolution spectra for 189 stars in the area of King 1. From their derived radial velocities, we determined an average velocity <V_r_>=-53.1+/-3.1km/s. From the strength of the infrared CaII lines in red giants we have determined an average metallicity of <[M/H]>=+0.07+/-0.08dex. From spectral synthesis, we have also estimated an {alpha}-elements abundance of <[{alpha}/M]>=-0.10+/-0.08dex.
- ID:
- ivo://CDS.VizieR/J/A+A/511/A38
- Title:
- Open clusters in third galactic quadrant
- Short Name:
- J/A+A/511/A38
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We aim to determine accurate distances and ages of eight open clusters in order to: (1) assess their possible binarity (2) provide probes to trace the structure of the Third Galactic Quadrant. Cluster reddenings, distances, ages and metallicities are derived from ZAMS and isochrone fits in UBVRI photometric diagrams. Field contamination is reduced by restricting analysis to stars within the cluster limits derived from star counts. Further membership control is done by requiring that stars have consistent positions in several diagrams and by using published spectral types.
- ID:
- ivo://CDS.VizieR/J/MNRAS/470/3937
- Title:
- 1876 open clusters multimembership catalog
- Short Name:
- J/MNRAS/470/3937
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The main objective of this work is to determine the cluster members of 1876 open clusters, using positions and proper motions of the astrometric fourth United States Naval Observatory (USNO) CCD Astrograph Catalog (UCAC4). For this purpose, we apply three different methods, all based on a Bayesian approach, but with different formulations: a purely parametric method, another completely non-parametric algorithm and a third, recently developed by Sampedro & Alfaro (2016MNRAS.457.3949S), using both formulations at different steps of the whole process. The first and second statistical moments of the members' phase-space subspace, obtained after applying the three methods, are compared for every cluster. Although, on average, the three methods yield similar results, there are also specific differences between them, as well as for some particular clusters. The comparison with other published catalogues shows good agreement. We have also estimated, for the first time, the mean proper motion for a sample of 18 clusters. The results are organized in a single catalogue formed by two main files, one with the most relevant information for each cluster, partially including that in UCAC4, and the other showing the individual membership probabilities for each star in the cluster area. The final catalogue, with an interface design that enables an easy interaction with the user, is available in electronic format at the Stellar Systems Group (SSG-IAA) web site (http://ssg.iaa.es/en/content/sampedro-cluster-catalog).
- ID:
- ivo://CDS.VizieR/J/A+A/637/A95
- Title:
- 16 open clusters UBVI and Gaia DR2 photometry
- Short Name:
- J/A+A/637/A95
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper has two main objectives: (1) To determine the intrinsic properties of sixteen faint and mostly unstudied open clusters in the poorly known sector of the Galaxy at 270{deg}-300{deg}, to probe the Milky Way structure in future investigations. (2) To address previously reported systematics in Gaia DR2 parallaxes by comparing the cluster distances derived from photometry with those derived from parallaxes. Deep UBVI photometry of 16 open clusters was carried out. Observations were reduced and analyzed in an automatic way using the ASteCA package to get individual distances, reddening, masses, ages and metallicities. Photometric distances were compared to those obtained from a Bayesian analysis of Gaia DR2 parallaxes. Ten out of the sixteen clusters are true or highly probable open clusters. Two of them are quite young and follow the trace of the Carina Arm and the already detected warp. The rest of the clusters are placed in the interarm zone between the Perseus and Carina Arms as expected for older objects. We found that the cluster van den Berg-Hagen 85 is 7.5x10^9^yrs old becoming then one of the oldest open cluster detected in our Galaxy so far. The relationship of these ten clusters with the Galaxy structure in the solar neighborhood is discussed. The comparison of distances from photometry and parallaxes data, in turn, reveals a variable level of disagreement. Various zero point corrections for Gaia DR2 parallax data recently reported were considered for a comparison between photometric and parallax based distances. The results tend to improve with some of these corrections. Photometric distance analysis suggest an average correction of ~+0.026mas (to be added to the parallaxes). The correction may have a more intricate distance dependency, but addressing that level of detail will require a larger cluster sample.