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Start Over Subject open star clusters Publisher CDS
741. ONC population data from WFI observations
ID:
ivo://CDS.VizieR/J/ApJ/748/14
Title:
ONC population data from WFI observations
Short Name:
J/ApJ/748/14
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a new census of the Orion Nebula Cluster over a large field of view (>~30'x30'), significantly increasing the known population of stellar and substellar cluster members with precisely determined properties. We develop and exploit a technique to determine stellar effective temperatures from optical colors, nearly doubling the previously available number of objects with effective temperature determinations in this benchmark cluster. Our technique utilizes colors from deep photometry in the I band and in two medium-band filters at {lambda}~753 and 770nm, which accurately measure the depth of a molecular feature present in the spectra of cool stars. From these colors we can derive effective temperatures with a precision corresponding to better than one-half spectral subtype, and importantly this precision is independent of the extinction to the individual stars. Also, because this technique utilizes only photometry redward of 750nm, the results are only mildly sensitive to optical veiling produced by accretion. Completing our census with previously available data, we place some 1750 sources in the Hertzsprung-Russell diagram and assign masses and ages down to 0.02M_{sun}_. At faint luminosities, we detect a large population of background sources which is easily separated in our photometry from the bona fide cluster members. The resulting initial mass function of the cluster has good completeness well into the substellar mass range, and we find that it declines steeply with decreasing mass. This suggests a deficiency of newly formed brown dwarfs in the cluster compared to the Galactic disk population.
742. On the metallicity of open clusters. II.
ID:
ivo://CDS.VizieR/J/A+A/561/A93
Title:
On the metallicity of open clusters. II.
Short Name:
J/A+A/561/A93
Date:
21 Oct 2021
Publisher:
CDS
Description:
The literature was searched for [Fe/H] estimates of individual member stars of open clusters (OCs) based on the analysis of high-resolution spectra. The lower limit for spectral resolving power (R={lambda}/{Delta}{lambda}) was set to 25000, and the lower limit for signal-to-noise ratio was set to 50. We searched the PASTEL database (2010A&A...515A.111S, Cat. B/pastel) and the recent literature for such metallicity determinations in references posterior to 1990 and until June 2013. Only stars with an effective temperature lower than 7000K were included to avoid rapid rotators and chemical peculiarities. We eliminated confirmed non-members, spectroscopic binaries, and chemically peculiar stars and kept only stars with a high probability of membership. This resulted in a list of 571 stars in 86 OCs, with 830 metallicity determinations from 94 papers, which we call the starting sample.
743. On the metallicity of open clusters. III.
ID:
ivo://CDS.VizieR/J/A+A/585/A150
Title:
On the metallicity of open clusters. III.
Short Name:
J/A+A/585/A150
Date:
21 Oct 2021
Publisher:
CDS
Description:
Open clusters are known as excellent tools for various topics in Galactic research. For example, they allow accurately tracing the chemical structure of the Galactic disc. However, the metallicity is known only for a rather low percentage of the open cluster population, and these values are based on a variety of methods and data. Therefore, a large and homogeneous sample is highly desirable. In the third part of our series we compile a large sample of homogenised open cluster metallicities using a wide variety of different sources. These data and a sample of Cepheids are used to investigate the radial metallicity gradient, age effects, and to test current models. We used photometric and spectroscopic data to derive cluster metallicities. The different sources were checked and tested for possible offsets and correlations. In total, metallicities for 172 open cluster were derived. We used the spectroscopic data of 100 objects for a study of the radial metallicity distribution and the age-metallicity relation. We found a possible increase of metallicity with age, which, if confirmed, would provide observational evidence for radial migration. Although a statistical significance is given, more studies are certainly needed to exclude selection effects, for example. The comparison of open clusters and Cepheids with recent Galactic models agrees well in general. However, the models do not reproduce the flat gradient of the open clusters in the outer disc. Thus, the effect of radial migration is either underestimated in the models, or an additional mechanism is at work. Apart from the Cepheids, open clusters are the best tracers for metallicity over large Galactocentric distances in the Milky Way. For a sound statistical analysis, a sufficiently large and homogeneous sample of cluster metallicities is needed. Our compilation is currently by far the largest and provides the basis for several basic studies such as the statistical treatment of the Galactic cluster population, or evolutionary studies of individual star groups in open clusters.
744. Open Cluster Data 5th Edition
ID:
ivo://CDS.VizieR/VII/92A
Title:
Open Cluster Data 5th Edition
Short Name:
VII/92A
Date:
21 Oct 2021
Publisher:
CDS
Description:
This is a computer readable catalogue of open cluster data compiled by Gosta Lynga, Lund Observatory, Box 43, S-221 00 Lund, Sweden. The present file mainly details the structure of the file "catalog"; please refer to the file "intro" for more details about the parameters. Further errors have been corrected at CDS: see below the "Historical Notes" section. A few questions still remain (see section "Problems" below)
745. Open-cluster density profiles
ID:
ivo://CDS.VizieR/J/MNRAS/456/3757
Title:
Open-cluster density profiles
Short Name:
J/MNRAS/456/3757
Date:
21 Oct 2021
Publisher:
CDS
Description:
Surface and spatial radial density profiles in open clusters are derived using a kernel estimator method. Formulae are obtained for the contribution of every star into the spatial density profile. The evaluation of spatial density profiles is tested against open-cluster models from N-body experiments with N=500. Surface density profiles are derived for seven open clusters (NGC 1502, 1960, 2287, 2516, 2682, 6819 and 6939) using Two-Micron All-Sky Survey data and for different limiting magnitudes. The selection of an optimal kernel half-width is discussed. It is shown that open-cluster radius estimates hardly depend on the kernel half-width. Hints of stellar mass segregation and structural features indicating cluster non-stationarity in the regular force field are found. A comparison with other investigations shows that the data on open-cluster sizes are often underestimated. The existence of an extended corona around the open cluster NGC 6939 was confirmed. A combined function composed of the King density profile for the cluster core and the uniform sphere for the cluster corona is shown to be a better approximation of the surface radial density profile.The King function alone does not reproduce surface density profiles of sample clusters properly. The number of stars, the cluster masses and the tidal radii in the Galactic gravitational field for the sample clusters are estimated. It is shown that NGC 6819 and 6939 are extended beyond their tidal surfaces.
746. Open Cluster Interstellar Matter Database
ID:
ivo://CDS.VizieR/VII/106
Title:
Open Cluster Interstellar Matter Database
Short Name:
VII/106
Date:
21 Oct 2021
Publisher:
CDS
Description:
This catalog is a compilation of the characteristics of 128 open clusters and the interstellar medium associated with them. It is distributed as the "OCISM Database" which is the set of data files, processing and analysis software written in FORTRAN, and the supporting documentation. As provided by the author, the data are in a multi-record format which is best accessed with the author's software. The clusters in this database have been relatively well-studied, have declinations greater than -20 deg., are between 1 and 5 kpc distant, and are younger than 100 million years old. Characteristics compiled for these clusters include cluster identification, spatial coordinates, radial velocities (of stellar clusters, H II regions, and molecular clouds), proper motions, distance, angular diameter, linear diameter, age, mass (based on stellar and atomic gas, ionized gas, molecular clouds, and dust determinations), visual extinction, and reddening.
747. Open cluster kinematics with Gaia DR2
ID:
ivo://CDS.VizieR/J/A+A/619/A155
Title:
Open cluster kinematics with Gaia DR2
Short Name:
J/A+A/619/A155
Date:
21 Oct 2021
Publisher:
CDS
Description:
The distribution of open clusters in the 6D phase space is revisited with Gaia DR2. The weighted mean radial velocity (RV) of open clusters was determined, using the most probable members available from a previous astrometric investigation that also provided mean parallaxes and proper motions. Those parameters, all derived from Gaia DR2 only, were combined to provide the 6D phase-space information of 861 clusters.
748. Open cluster King 1 photometry
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.
749. Open cluster Pis 20
ID:
ivo://CDS.VizieR/J/A+AS/111/85
Title:
Open cluster Pis 20
Short Name:
J/A+AS/111/85
Date:
21 Oct 2021
Publisher:
CDS
Description:
The very young open cluster Pis 20 has been investigated using CCD UBVR photometry. New blue faint members were found down to V=19mag. With them we obtain a better definition of the lower cluster main sequence. Using the fitting method, we derive a cluster distance of d=3600pc (V_0_-M_V_=12.80). The mean color excess is <E_B-V_>=1.24mag.
750. Open cluster properties with Gaia and LAMOST
ID:
ivo://CDS.VizieR/J/A+A/640/A127
Title:
Open cluster properties with Gaia and LAMOST
Short Name:
J/A+A/640/A127
Date:
01 Mar 2022 11:35:22
Publisher:
CDS
Description:
In Gaia DR2, an unprecedented high level of precision has been reached at sub-milliarcsecond for astrometry and millimagnitudes for photometry. Using cluster members identified with the astrometry and photometry in Gaia DR2, we can obtain a reliable determination of cluster properties. However, because of the shortcomings of Gaia spectroscopic observations in dealing with densely crowded cluster regions, the RVs and metallicity values for cluster member stars from Gaia DR2 are still lacking. It is necessary to combine the Gaia data with the data from large spectroscopic surveys, such as LAMOST, APOGEE, GALAH, and Gaia-ESO. In this study, we aim to improve the cluster properties by combining the LAMOST spectra. In particular, we provide the list of cluster members with spectroscopic parameters as an add-value catalog in LAMOST DR5, which can be used to perform detailed study for a better understanding on the stellar properties, by using their spectra and fundamental properties from the host cluster. We cross-matched the spectroscopic catalog in LAMOST DR5 (Luo et al., 2019, Cat. V/164) with the identified cluster members in Cantat-Gaudin et al. (2018, Cat. J/A+A/615/A49). We then used members with spectroscopic parameters to derive statistical properties of open clusters.We obtained a list of 8811 members with spectroscopic parameters and a catalog of 295 cluster properties. In addition, we study the radial and vertical metallicity gradient and age-metallicity relation with the compiled open clusters as tracers, finding slopes of -0.053+/-0.004dex/kpc, -0.252+/-0.039dex/kpc and 0.022+/-0.008dex/Gyr, respectively. Both slopes of metallicity distribution relation for young clusters (0.1Gyr<Age<2Gyr) and the age-metallicity relation for clusters within 6Gyr are consistent with literature results. In order to fully study the chemical evolution history in the disk, more spectroscopic observations for old and distant open clusters are needed for further investigation.

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