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J/A+AS/122/9 CCD UBVRI Photometry of 4 open clusters (Sagar+ 1997)
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Multicolour deep CCD photometric study of the moderately young southern open
star clusters NGC 3228, NGC 4103, NGC 5662 and NGC 6087
Sagar R., Cannon R.D.
<Astron. Astrophys. Suppl. Ser. 122, 9 (1997)>
=1997A&AS..122....9S (SIMBAD/NED BibCode)
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ADC_Keywords: Clusters, open ; Photometry, UBVRI
Keywords: HR diagram - stars: evolution -
open clusters and associations: individual: NGC 3228, NGC 4103,
NGC 5662, NGC 6087
Abstract:
CCD observations in the U, B, V, R and I passbands have been used to
generate colour-colour and deep colour-magnitude diagrams for the
young open star clusters NGC 3228, NGC 4103, NGC 5662 and NGC 6087.
The sample consists of about 2000 stars reaching down to V=20mag. The
interstellar extinction across the face of the imaged cluster regions
seems to be uniform with average values of E(B-V)=0.31, 0.34 and
0.22mag for NGC 4103, NGC 5662 and NGC 6087 respectively. The
distances to the clusters NGC 3228, NGC 4103, NGC 5662 and NGC 6087
have been estimated as 0.5+/-0.05, 2.0+/-0.3, 0.8+/-0.1 and
1.0+/-0.1kpc respectively, while the corresponding ages estimated from
the theoretical stellar evolutionary isochrones fitted to the bright
proper motion cluster members are ~100, 30, 80 and 65Myr respectively.
Present data are consistent with the membership of the Cepheid
variable V Cen to NGC 5662 and of S Norm to NGC 6087. Heavy
contamination by foreground and background field stars has
unfortunately made it impossible to reach definite conclusions about
the faint luminosity function, and the data do not reach faint enough
limits to investigate pre-main sequence stars.
Objects:
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RA (2000) DE Designation(s)
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10 21.8 -51 43 NGC 3228 = C 1019-514
12 06.7 -61 15 NGC 4103 = C 1204-609
14 35.2 -56 33 NGC 5662 = C 1431-563
16 18.9 -57 54 NGC 6087 = C 1614-577
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table6 55 408 Relative positions and UBVRI mag in NGC 3228
table7 62 288 Relative positions and UBVRI mag in NGC 4103
table8 80 502 Relative positions and UBVRI mag in NGC 5662
table9a 56 418 Relative positions and UBVRI mag in
Region 1 of NGC 6087
table9b 63 381 Relative positions and UBVRI mag in
Regions 2 and 3 of NGC 6087
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Byte-by-byte Description of file: table6 table7 table8 table9b
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Bytes Format Units Label Explanations
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2- 4 I3 --- SeqNum Sequential star number
5- 12 F8.2 pix Xpos X position
13- 20 F8.2 pix Ypos Y position
21- 27 F7.2 mag Vmag V magnitude
28- 34 F7.2 mag U-B ? U-B colour index
35- 41 F7.2 mag B-V ? B-V colour index
42- 48 F7.2 mag V-R ? V-R colour index
49- 55 F7.2 mag V-I ? V-I colour index
56- 80 A25 --- Name Other identifications (1)
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Note (1): Prefixes are:
W: Wesselink, 1969MNRAS.146..329W
MV: Moffat & Vogt, 1973A&AS...10..135M
H: Haug, 1978A&AS...34..417H
K: King, 1980, J. Proc. R. Soc. N.S.W. 113, 7
C: Claria et al., 1991MNRAS.249..193C
L: Landoldt, 1964ApJS....8..329L
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Byte-by-byte Description of file: table9a
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Bytes Format Units Label Explanations
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2- 4 I3 --- SeqNum Sequential star number
5- 12 F8.2 pix Xpos X position
13- 20 F8.2 pix Ypos Y position
21- 27 F7.2 mag Vmag V magnitude
28- 34 F7.2 mag U-B ? U-B colour index
35- 41 F7.2 mag B-V ? B-V colour index
42- 48 F7.2 mag V-I V-I colour index
49- 80 A32 --- Name Other identifications (1)
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Note (1): L: Landoldt (1964ApJS....8..329L)
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Acknowledgements: Ram Sagar <sagar@iiap.ernet.in>
References:
Claria et al. 1991, MNRAS 249, 193 =1991MNRAS.249..193C
Haug 1978, A&AS 34, 417 =1978A&AS...34..417H
King 1980, J. Proc. R. Soc. N.S.W. 113, 7 (= Sydney Obs. Papers No. 87)
Landoldt 1964, ApJS 8, 329 =1964ApJS....8..329L
Moffat & Vogt 1973, A&AS 10, 135 =1973A&AS...10..135M
Wesselink 1969, MNRAS 146, 329 =1969MNRAS.146..329W
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(End) Patricia Bauer [CDS] 24-Jul-1996