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J/A+A/477/165     Nearby open clusters tidal radii and masses  (Piskunov+, 2008)
Tidal radii and masses of open clusters.
    Piskunov A.E., Schilbach E., Kharchenko N.V., Roeser S., Scholz R.-D.
   <Astron. Astrophys. 477, 165 (2008)>
   =2008A&A...477..165P
ADC_Keywords: Clusters, open ; Morphology

Keywords: Galaxy: open clusters and associations: general -
          solar neighbourhood - Galaxy: stellar content

Abstract:
    In a previous paper we obtained King's parameters for 236 of 650
    Galactic open clusters identified in the ASCC-2.5 (Kharchenko, 2001,
    Cat. I/280). Our aims is the estimate tidal radii by use of
    observable parameters available for all clusters. Bias-free results
    are required. We use methods of stellar statistics and develop a
    semi-empirical model of open clusters.

Description:
    The table presents tidal radii and masses of 650 Galactic open
    clusters. The tidal radii are derived from a relation between a
    semi-major axis A of the density distributions of cluster members and
    fitted King radii (J/A+A/468/151). The cluster masses are found from
    cluster tidal radii assuming that the latter are good approximations
    of limiting radii for local clusters moving at nearly circular orbits.
    The clusters are a sample of the Catalogue of Open Cluster Data and
    their members are selected from the high-precision, homogeneous
    all-sky catalogue ASCC-2.5 (Kharchenko, 2001, Cat. I/280). The
    clusters in the table are sorted according to their order in the COCD.

File Summary:

       FileName      Lrecl  Records   Explanations

ReadMe            80        .   This file
table.dat        124      650   Tidal radii and masses for 650 open clusters


See also:
          I/280 : All-sky Compiled Cat. of 2.5 million stars (Kharchenko, 2001)
 J/A+A/438/1163 : Catalogue of Open cluster Data (COCD) (Kharchenko+, 2005)
 J/A+A/440/403  : 109 new Galactic open clusters (COCD1) (Kharchenko+, 2005)
 J/A+A/468/151  : Nearby open clusters radii and masses (Piskunov+, 2007)


Byte-by-byte Description of file: table.dat

   Bytes Format Units      Label     Explanations

   1-  4  I4    ---        COCD      (1-520, 1001-1130) COCD number
   7- 23  A17   ---        Name      Cluster designation (NGC, IC or other) (1)
  25- 31  F7.2  deg        GLON      Galactic longitude
  32- 38  F7.2  deg        GLAT      Galactic latitude
  39- 46  F8.3  mag        DistMod   Distance modulus
  47- 52  F6.2  mag        E(B-V)    B-V Colour-excess
  53- 58  I6    pc         Dist      Distance
  59- 64  F6.2  [yr]       logt      Logarithm of age
  65- 70  F6.1  pc         rt        ?=-9.9 Tidal radius
  71- 76  F6.1  pc         e_rt      ?=-9.9 rms error rt
  77- 85  F9.3  [solMass]  logM      ?=-9.999 Logarithm of cluster mass
  86- 94  F9.3  [solMass]  e_logM    ?=-9.999 rms error of logM
  95-100  F6.1  pc         rtA       Tidal radius derived from semi-major axis A
 101-106  F6.1  pc         e_rtA     rms error of rtA
 107-115  F9.3  [solMass]  logMA     Log of Cluster mass from semi-major axis A
 116-124  F9.3  [solMass]  e_logMA   rms error of logMA

Note (1): There are clusters which overlap in the plane of the sky some
     of which also have common members. The most prominent example is
     the "double cluster" h and chi Per (COCD numbers 29 and 30). Their
     semi-major axes A are overestimated due to the relatively large number
     of common members, and so are their individual tidal radii and masses.


Acknowledgements:
    Ralf-Dieter Scholz, rdscholz(at)aip.de
(End)                                        Patricia Vannier [CDS]  03-Dec-2007