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COCDEXT1 - COCD: Catalog of Open Cluster Data First Extension

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Overview

This table contains a list of 130 Galactic open clusters, found in the All-Sky Compiled Catalogue of 2.5 Million Stars (ASCC-2.5) and not included in the original Catalog of Open Cluster Data (COCD): it is known as the 1st Extension of the COCD (COCD-1). For these new clusters, the authors determined a homogeneous set of astrophysical parameters such as size, membership, motion, distance and age. In their previous work (the Browse table COCD based on the CDS Cat. J/A+A/438/1163), 520 already-known open clusters out of a sample of 1700 clusters from the literature were confirmed in the ASCC-2.5 using independent, objective methods. Using these same methods, the whole sky was systematically screened for new clusters. The newly detected clusters show the same distribution over the sky as the known ones. It is found that without the a priori knowledge about existing clusters the authors' search lead to clusters which are, on average, brighter, have more members and cover larger angular radii than the 520 previously-known ones.

On the basis of data on about 6,200 possible members (including about 2,200 most probable ones) and homogeneous methods of cluster parameter determination, the angular sizes of cluster cores and coronae, cluster heliocentric distances, colour-excesses, mean proper motions, and ages of 130 clusters and mean radial velocities of 69 clusters were established and collected in the COCD-1. Clusters in the catalogue are numbered in order of increasing J2000.0 Right Ascension.

The 1st Extension of the Open Cluster Diagrams Atlas (OCDA-1) presents a set of open cluster diagrams used for the determination of parameters of the 130 newly discovered open clusters, and is intended to illustrate the quality of the constructed cluster membership, and the accuracy of the derived cluster parameters. Every diagram presents relations between various stellar data from the all sky catalog ASCC-2.5(Kharchenko, 2001, CDS Cat. <I/280>) in the area of the specific cluster. There are five diagrams provided for every cluster in the Atlas: the area map, the density profile, the vector point diagram, the "magnitude equation" (proper motion in each coordinate versus V magnitude) diagram, and the color-magnitude diagram. The 130 OCDA-1 PostScript plots (one file per cluster) are available as a remote data product for all of the entries in this table.


Catalog Bibcode

2005A&A...440..403K

References

109 new Galactic open clusters.
    Kharchenko N.V., Piskunov A.E., Roeser S., Schilbach E., Scholz R.-D.
   <Astron. Astrophys., 440, 403-408 (2005)>
   =2005A&A...440..403K

Provenance

This table was created by the HEASARC in May 2011 based on CDS Catalog J/A+A/440/403/ files cluster.dat and notes.dat.

Data Products

The atlas files (one for each cluster) in the OCDA-1 are stored at CDS. Each file is in a compressed PostScript format. The CDS describes these files as follows:
    Each plot contains a header, five diagrams and selected cluster
    parameters from the 1st Extension of the Catalogue of Open Cluster
    Data (COCD-1). The header gives the equatorial coordinates of the
    newly determined cluster center, the cluster number and designation in
    the file index.dat and reference to note file.

    The panels present spatial, kinematic and evolutionary information.
    The upper row: the left panel is a sky map of the cluster neighborhood
    (MAP) constructed with stars from the CDS catalog <I/280>, and the right
    panel is the colour-magnitude diagram (CMD). The bottom row: the left
    panel shows density profile diagram (DPD) - radial profiles of the
    projected density, the middle panel is the vector point diagram of
    proper motions (VPD), and the two right panels are "magnitude
    equation" diagrams (MED) - proper motions versus magnitude.

 Common designation on MAP, CMD, VPD, MED:

    Green symbols: stars within the cluster radius;
    Black symbols: the most probable (1sigma members) within of cluster core;
      Red symbols: the most probable (1sigma members) outside of the core
                   and within cluster corona.

 MAP:
      Stars are displayed as circles.
      The circle size corresponds to stellar magnitude ranged in six Vmag
      intervals: <4.0, 4.0-6.0, 6.0-8.0, 8.0-10.0, 10.0-12.0, >12.0.
     Cyan open circles: stars outside of cluster area (are shown in MAP only);
    Green open circles: stars inside of cluster area;
            Blue cross: cluster center selected in this study;
        Magenta pulses: centers of other clusters (from Dias et al., 2004)
                        visible (if any) in this map;
     Solid blue circle: cluster core border (rcore);
    Dashed blue circle: cluster border (rcl).

 CMD:
    Solid blue lines outline a domain of 100% photometric cluster members.
    - the left border is the empirical ZAMS of Schmidt-Kaler;
    - the right border is composed as it is described by Kharchenko et al.
      (2004, Cat. J/other/AN/325.740);
    For convenience blue edge is extended in comparison to the
    Schmidt-Kaler ZAMS up to MV= -7.0, (B-V)0= -0.33;
    - Solid cyan lines indicate blue and red borders of the evolved Main
      Sequence, (see Kharchenko et al., 2005A&A...440..403K for definitions);
    - Bars indicates the rms errors of V and (B-V) for 1sigma members;
      Magenta solid curves are Post- and Pre-MS isochrones closest to the
      determined cluster age;
    - Large magenta open circles mark stars selected for age determination
      (see Kharchenko et al. 2005A&A...440..403K for details).

 VPD: Bars indicate the rms errors of PM for 1sigma members.

 MED:
    - Magenta solid lines correspond to determined average proper motion
      of the cluster;
    - Bars indicate the rms errors of PM for 1-sigma members.

 DPD:
    - Green solid line is constructed for all stars in the cluster area;
    - Magenta solid line is constructed for all members with membership
      probability P>1% (i.e. 1,2,3sigma members);
    - Black solid line is constructed for 1sigma members only;
    - Solid blue line indicates cluster core radius;
    - Dashed blue line indicates cluster radius;

 Notes on selected cluster parameters shown in the CMD panel:
    - The rms errors of determined PM and RV are shown in parentheses;
    - Distance modulus corresponds to indicated d and E(B-V) values;
    - Number of stars selected for log t determination is shown after
      the 'pound' or 'hash mark' symbol;

Parameters

Source_Number
A running identification number n from 1 to 130 for each cluster in this table, in order of increasing J2000.0 Right Ascension. Notice that these source numbers are independent of those in the main COCD table. In the CDS version of this table, the authors have also used a running number scheme starting with 1001 and ending in 1130 to avoid this duplication, but the Dictionary of Nomenclature of Celestial Objects recommends using the numbering scheme as given herein.

Name
The cluster designation as recommended by the Dictionary of Nomenclature of Celestial Objects, using the '[KPR2005]' prefix (for Kharchenko, Piskunov, Roeser 2005) and the source number as given here. Alternative designations for these clusters have also been used: for example, 'ASCC n', where n is the source number, is used in the reference paper, and the form 'COCD 1000+n' has also been used in the literature, e.g., '[KPR2005] 22' = 'ASCC 22' = 'COCD 1022'.

Alt_Name
A commonly used designation for the cluster, if one exists.

RA
The Right Ascension of the adopted cluster center in the selected equinox. This was given in J2000.0 coordinates to a precision of 0.001 hours (3.6 seconds of time) in the original table.

Dec
The Declination of the adopted cluster center in the selected equinox. This was given in J2000.0 coordinates to a precision of 0.01 degrees (36 arcseconds) in the original table.

LII
The Galactic Longitude of the adopted cluster center.

BII
The Galactic Latitude of the adopted cluster center.

Core_Radius
The angular radius of the core of the cluster, in degrees. The authors assumed a centrally symmetric distribution of the cluster members and considered only two structural components, a core with a radius r1, and a corona with a radius r2. The core radius corresponds to the distance where the decrease of stellar surface density stops abruptly. For each cluster, the core and corona radii were checked by visual inspection, and the constraints set by the corresponding vector point diagram (VPD) of the proper motions and the color-magnitude diagram (CMD) were always taken into account.

Cluster_Radius
The angular radius of the corona of the cluster, in degrees. The authors assumed a centrally symmetric distribution of the cluster members and considered only two structural components, a core with a radius r1, and a corona with a radius r2. The corona radius (i.e. the actual radius of the cluster) is defined as the distance from the cluster centre where the surface density of stars becomes equal to the average density of the surrounding field (see Fig. 1b in the 2005 reference paper). For each cluster, the core and corona radii were checked by visual inspection, and the constraints set by the corresponding vector point diagram (VPD) of the proper motions and the color-magnitude diagram (CMD) were always taken into account.

Rad_Vel
The average radial velocity of the selected stars in the cluster, in km/s.

Rad_Vel_Error
The standard error in the average radial velocity of the selected stars in the cluster, in km/s.

Num_Rad_Vel_Stars
The number of cluster stars used for the radial velocity calculation.

PM_RA
The average cluster proper motion in the Right Ascension direction, muRA * cos(Dec), in milliarcseconds per year (mas/yr).

PM_RA_Error
The standard error in the average cluster proper motion in the Right Ascension direction, muRA * cos(Dec), in milliarcseconds per year (mas/yr).

PM_Dec
The average cluster proper motion in the Declination direction, muDec, in milliarcseconds per year (mas/yr).

PM_Dec_Error
The standard error in the average cluster proper motion in the Declination direction, muDec, in milliarcseconds per year (mas/yr).

PM_LII
The average proper motion in the Galactic Longitude direction, mulii * cos(bii), in milliarcseconds per year (mas/yr).

PM_BII
The average proper motion in the Galactic Latitude direction, mubii, in milliarcseconds per year (mas/yr).

Num_Cluster_Stars
The number of the most probable (1-sigma) cluster members. For each cluster, the membership determination was based on a comprehensive common analysis of several diagrams derived with ASCC-2.5 data: a sky chart referring to the cluster, the radial distribution F(r) of the projected stellar density, a vector point diagram (VPD) of the proper motions, the magnitude dependence of the proper motion components, and a colour-magnitude diagram (CMD).

Distance
The cluster distance, D, in parsecs (pc). The methodology used to estimate D is discussed in Section 3.1 of the COCD paper (Kharchenko et al. 2005, A&A, 438, 1163).

E_BV
The reddening (color excess), E(B-V), towards the cluster, in magnitudes. The methodology used to estimate E(B-V) is discussed in Section 3.1 of the COCD paper (Kharchenko et al. 2005, A&A, 438, 1163).

Distance_Modulus
The apparent distance modulus of the cluster, i.e., the quantity (5 * log (D)) - 5.0 + AV, where A_V- is the visual extinction towards the cluster and is assumed to be 3.1 * E(B-V).

Log_Age
The logarithm of the average age of the stars in the cluster, log t, in years. The methodology used to estimate cluster ages is discussed in Section 5 of the COCD paper (Kharchenko et al. 2005, A&A, 438, 1163).

Num_Log_Age_Stars
The number of cluster stars used for the age calculation.

Notes
Individual notes concerning the cluster.


Contact Person

Questions regarding the COCDEXT1 database table can be addressed to the HEASARC User Hotline.

Page Author: Browse Software Development Team
Last Modified: 28-Aug-2012