J/A+A/374/504 UBVI photometry of NGC 7654 (M52) (Pandey+, 2001)
NGC 7654: An interesting cluster to study star formation history
Pandey, A.K., Nilakshi, Ogura, K., Sagar, R., Tarusawa, K.
<Astron. Astrophys. 374, 504 (2001)>
=2001A&A...374..504P 2001A&A...374..504P
ADC_Keywords: Clusters, open ; Photometry, CCD ; Photometry, UBVRI
Keywords: open cluster; spatial structure, mass function, star formation
Abstract:
CCD UBVIc photometry in a wide field around the open cluster NGC 7654
has been carried out for ∼17860 stars, down to V∼20. The reddening
across the cluster region is found to be variable with E(B-V) from
0.46mag to 0.80mag. The cluster is situated at a distance of
1380±70pc. The colour magnitude diagrams show a large age spread in
the ages. Star formation was biased towards relatively higher masses
during the early phase of star formation whereas most of the low mass
stars of the cluster were formed during the later phase. The star
formation seems to have been a gradual process that proceeded
sequentially in mass and terminated with the formation of most massive
stars. The present data do not support a uniform mass function (MF)
for different regions in the cluster.
Description:
File table2.dat contains the photometric data of the stars in the
field of NGC 7654. The stars are numbered in the increasing order of
their radial distance from the cluster center.
Objects:
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RA (2000) DE Designation(s)
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23 24 12 +61 35.0 NGC 7654 = M 52
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 114 17862 UBVIc photometric data of the stars in the field
of NGC 7654
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 6 I6 --- No Identification number of the stars
8- 15 F8.2 pix Xpos Pixel coordinate (1)
17- 24 F8.2 pix Ypos Pixel coordinate (1)
28- 33 F6.3 mag Vmag Magnitude in the V (Johnson) band
35- 41 F7.3 mag B-V ? B-V colour index
42 A1 --- n_B-V [*] *: no value
44- 49 F6.3 mag V-I ? V-I (Cousins) colour index
50 A1 --- n_V-I [*] *: no value
52- 57 F6.3 mag U-B ? U-B colour index
58 A1 --- n_U-B [*] *: no value
61- 65 F5.3 mag e_Imag ? Errors in the I (Cousins) band
66 A1 --- n_Imag [*] no value
69- 73 F5.3 mag e_Vmag Errors in the V (Johnson) band
77- 81 F5.3 mag e_Bmag ? Errors in the B (Johnson) band
82 A1 --- n_Bmag [*] *: no value
85- 89 F5.3 mag e_Umag ? Errors in the U (Johnson) band
90 A1 --- n_Umag [*] *: no value
93- 97 F5.3 --- chi χ parameter in the V (Johnson) band (3)
100- 105 F6.3 --- Sharp Sharpness parameter in the V (Johnson) band (2)
106- 114 F9.3 arcsec r Radial distance of the stars from the cluster
center (X=855, Y=755)
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Note (1): Pixel coordinates:
* Origin: X=0, Y=0
* Orientation East: X=0,
West: X=1600;
South: Y=0,
North: Y=1600
* Scale: 1 pix = 1.5arcsec
Note (2): the sharpness parameter measures how well the PSF fits the object.
Note (3): the χ parameter measures the average rms deviation to the
PSF fit normalized to the expected errors.
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Acknowledgements: A.K. Pandey
(End) Patricia Bauer [CDS] 12-Jul-2001