J/A+A/240/262 UBVR photometry of the open cluster King 2 (Aparicio+ 1990)
CCD UBVR photometry of the old rich open cluster King 2:
comparison with theoretical models.
Aparicio A., Bertelli G., Chiosi C., Garcia-Pelayo J.M.
<Astron. Astrophys. 240, 262 (1990)>
=1990A&A...240..262A 1990A&A...240..262A
ADC_Keywords: Clusters, open ; Photometry, CCD ; Photometry, UBVRI
Keywords: clusters: open - stars: H-R diagrams - stars: structure
Abstract:
In this paper we present the Johnson-Cousins UBVR CCD photometry of
the stars in King 2, an old open cluster towards the galactic
anticenter. We have obtained the colour-magnitude diagram, the colour
excess, the reddening, an estimate of the metallicity, and the
distance modulus. The comparison of the observational colour-magnitude
diagram with the theoretical simulations based on stellar models with
convective overshoot shows that a major revision of the model
structure is required. To this aim, we explore the possibility that
the formulation of convective overshoot for stars in the mass range 1
to 2M☉ ought to be different from the one currently in use. The
point of major uncertainty that we see to affect the stars in this
domain is whether or not convective overshoot may erode the gradient
in molecular weight in the regions surrounding the convective core. We
find that models, in which this is not allowed to occur, better fit
the overall morphology of the colour-magnitude diagram of King 2. In
addition to this, analyzing the width of the main sequence band we
suggest that a significant fraction of the stars are members of binary
systems, and evaluate the range spanned by their mass ratios. Finally,
we derive the luminosity function and the mass function for the main
sequence stars of the cluster.
Objects:
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RA (2000) DE Designation(s)
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00 51 00.0 +58 11 00 Cl King 2 = C 0048+579
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 61 748 Photometric data of King 2
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- ABC Sequential number, Cl* King 2 ABC NNN in Simbad
5- 10 F6.2 pix Xpos X position (1)
12- 18 F7.2 pix Ypos Y position (1)
20- 24 F5.2 mag Vmag Johnson V magnitude
26- 29 F4.2 mag e_Vmag rms uncertainty on Vmag
31- 35 F5.2 mag U-B ?=- Johnson U-B colour index
37- 40 F4.2 mag e_U-B ?=- rms uncertainty on U-B
42- 45 F4.2 mag B-V ?=- Johnson B-V colour index
47- 50 F4.2 mag e_B-V ?=- rms uncertainty on B-V
52- 56 F5.2 mag V-Rc ?=- Johnson-Cousins V-R colour index
58- 61 F4.2 mag e_V-Rc ?=- rms uncertainty on V-Rc
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Note (1): North at the left and east at the bottom. 1pix=15µm=0.254".
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History:
Prepared via OCR at CDS.
(End) James Marcout, Patricia Bauer [CDS] 27-Jun-2003