J/MNRAS/299/1 BVI photometry in four open clusters (Sagar+, 1998)
BVI CCD photometry of the distant open star clusters
Berkeley 81, Berkeley 99, NGC 6603 and NGC 7044.
Sagar R., Griffiths W.K.
<Mon. Not. R. Astron. Soc. 299, 1 (1998)>
=1998MNRAS.299....1S 1998MNRAS.299....1S (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Photometry, CCD
Keywords: stars: evolution - Hertzsprung-Russell (HR) diagram -
open clusters and associations: individual: Berkeley 81 -
open clusters and associations: individual: Berkeley 99 -
open clusters and associations: individual: NGC 6603 -
open clusters and associations: individual: NGC 7044
Abstract:
We present CCD observations for the distant northern open star
clusters Berkeley 81, Berkeley 99, NGC 6603 and NGC 7044 in BVI
photometric passbands. A total of 9900 stars have been observed in
fields of about 6x6arcmin2 of the sky around the clusters.
Colour-magnitude diagrams in V, (B-V) and V, (V-I) have been generated
down to V=22mag and, for the first time, such diagrams have been
produced for the clusters Berkeley 81 and Berkeley 99. The data serve
as a base for the study of mass functions and for comparison with
theoretical models. Analysis of the radial distribution of stellar
surface density indicates that the radius values for Berkeley 81,
Berkeley 99, NGC 6603 and NGC 7044 are 2.7, 2.8, 2.8 and 2.2arcmin
respectively. By fitting the latest convective core overshooting
isochrones to the colour-magnitude diagram and using its morphological
features, reddenings, distances and ages of the star clusters have
been determined. Broad but well-defined main sequences with stellar
evolutionary effects in the brighter stars are clearly visible in
colour-magnitude diagrams of all the clusters under study. Some blue
stragglers along with well-developed giant branches and red giant
clumps are also clearly seen in all of them. The clusters studied here
are located at a distance of ∼3 kpc, except for Berkeley 99 which is
located at a distance of 4.9kpc. Their linear sizes lie between 3.8
and 8.0pc; E(B-V) values range from 0.3 to 1.0mag, while their ages
are between 0.5 and 3.2Gyr. Thus the star clusters studied here are of
intermediate and high age but are compact and distant objects.
Objects:
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RA (2000) DE Designation(s)
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19 01 36 -00 31.0 Berkeley 81
23 21 36 +71 45.0 Berkeley 99
18 18 24 -18 25.0 NGC 6603
21 13 00 +42 29.0 NGC 7044
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 35 3301 Berkeley 81 field stars relative positions and
CCD BVI magnitudes
table4.dat 35 867 Berkeley 99 field stars relative positions and
CCD BVI magnitudes
table5.dat 41 3543 NGC 6603 field stars relative positions and
CCD BVI magnitudes
table6.dat 49 2197 NGC 7044 field stars relative positions and
CCD BVI magnitudes
tables.tex 78 11044 LaTeX version of tables
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See also:
J/AJ/106/1547 : UBV photometry in NGC 7044 (Aparicio+ 1993)
Byte-by-byte Description of file: table3.dat table4.dat table5.dat table6.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- SG Star number in the field
6- 12 F7.2 pix Xpos X coordinate (1)
14- 19 F6.2 pix Ypos Y coordinate (1)
21- 25 F5.2 mag Vmag magnitude
27- 30 F4.2 mag B-V ? B-V colour index
32- 35 F4.2 mag V-I V-I colour index
37- 49 A13 --- Name Other identification (2)
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Note (1): 1 pix = 0.74arcsec.
For the orientation, see Fig. 1-4 of the paper.
Note (2): B: Bica et al. (1993A&A...270..117B 1993A&A...270..117B) identification
K: Kaluzny (1989AcA....39...13K 1989AcA....39...13K) identification
A: Aparicio et al. (1993, Cat. J/AJ/106/1547)
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Acknowledgements: Ram Sagar
(End) Patricia Bauer [CDS] 19-Oct-1998