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J/A+A/372/71        King 5 and Berkeley 20 UBVRI photometry   (Durgapal+, 2001)
Multicolor CCD photometry of old open clusters: King 5 and Be 20
    Durgapal A.K., Pandey A.K., Mohan V.
   <Astron. Astrophys. 372, 71 (2001)>
   =2001A&A...372...71D
ADC_Keywords: Clusters, open ; Photometry, CCD ; Photometry, UBVRI

Keywords: Hertzsprung-Russel (HR) diagram - open clusters -
          individual: King 5; Be 20

Abstract:
    We present multicolour CCD photometry for two poorly studied open
    clusters (King 5 and Be 20). Photometry for a field near King 5 was
    also carried out to estimate the contamination by field stars. The
    colour magnitude diagrams (CMD) of the clusters show a well defined
    main sequence extending to the limit of the photometry, V~=20mag. The
    reddening for King 5, estimated from the colour-colour diagram, is
    ∼0.82, whereas that for Be 20 as estimated by comparing theoretical
    main-sequence (MS) with the observed MS is 0.10. The morphology of the
    CMDs indicates that these clusters are old. The CMD of Be 20 shows a
    globular cluster-like horizontal branch. In case of King 5 the
    comparison of observational CMDs with the standard isochrones of
    VandenBerg (1985ApJS...58..711V) indicates an apparent discrepancy
    between the shape of the turnoff and isochrones. The CMDs of King 5
    seem to be better understood in terms of stellar models with
    convective overshoot. The comparison of the CMDs with the stellar
    models by Bertelli et al. (1985A&A...150...33B) with convective
    overshoot produces a good fit for a metallicity Z=0.008 and an age of
    1Gyr for King 5 and 5Gyr for Be 20. An apparent distance modulus
    (m-M)=14.0 and 15.1 has been estimated for King 5 and Be 20
    respectively. They correspond to a distance of 1900±100pc and
    9026±480pc, respectively. The radial density distribution in King 5
    indicates that there is an excess of low mass stars in the outer
    region of the cluster, whereas the density distribution in Be 20 shows
    a good fit with the empirical King (1962AJ.....67..471K) model. For
    both clusters, observations have also been carried out to search for
    variable stars.
Objects:
    ---------------------------------------------
       RA  (2000)  DE       Designation(s)
    ---------------------------------------------
    03 14 36    +52 43.0    King 5
    05 33 00    +00 13.0    Berkeley 20
    ---------------------------------------------

File Summary:

       FileName      Lrecl  Records   Explanations

ReadMe            80        .   This file
table2.dat        80      470   Magnitude and colours of the stars in the
                                 field of King 5
table3.dat        80      189   Magnitude and colors of the stars in the
                                 nearby east region of King 5
table4.dat        80      362   Magnitude and colours of the stars in the
                                 field of Be 20


See also:
   J/A+AS/122/111 : Berkeley 64 and 69 stars UBVRI photometry (Pandey+, 1997)


Byte-by-byte Description of file: table2.dat table3.dat table4.dat

   Bytes Format Units   Label     Explanations

   1-  3  I3    ---     Seq       Sequential number in the field
   5- 10  F6.2  pix     Xpos      X position (1)
  12- 17  F6.2  pix     Ypos      Y position (1)
  19- 24  F6.3  mag     Vmag      V magnitude
  26- 31  F6.3  mag     U-B       ? (U-B) colour index
  33- 38  F6.3  mag     B-V       ? (B-V) colour index
  40- 44  F5.3  mag     V-R       ? (V-R) colour index
  46- 50  F5.3  mag     V-I       ? (V-I) colour index
  52- 56  F5.3  mag     e_Umag    ? Photometric error in U filter
  58- 62  F5.3  mag     e_Bmag    ? Photometric error in B filter
  64- 68  F5.3  mag     e_Vmag    ? Photometric error in V filter
  70- 74  F5.3  mag     e_Rmag    ? Photometric error in R filter
  76- 80  F5.3  mag     e_Imag    ? Photometric error in I filter

Note (1): 1 pix = 0.37".
          For King 5, the center coordinates are (227, 205)
          For Be 20, the center coordinates are (224, 220)


Acknowledgements: Alok Durgapal 

(End)                                          Patricia Bauer [CDS]  18-May-2001