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. =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 69 189 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