J/A+AS/145/365 BVI photometry of NGC 7790 (Gupta+, 2000)
A complete photometric study of the open cluster NGC 7790 containing
Cepheid variables.
Gupta A.C., Subramaniam A., Sagar R., Griffiths W.K.
<Astron. Astrophys. Suppl. Ser. 145, 365 (2000)>
=2000A&AS..145..365G 2000A&AS..145..365G
ADC_Keywords: Clusters, open ; Photometry, CCD ; Photometry, Cousins
Keywords: Galaxy: open clusters: individual: NGC 7790 - stars: evolution -
HR diagram
Abstract:
CCD photometry of the northern open star cluster NGC 7790 has been
carried out in BVI photometric passbands down to V∼21mag for 1150
stars of which for ∼700 stars, the data is obtained for the first
time. We derive the most reliable parameters for this cluster using
all the available photometric, spectroscopic and proper motion data.
The interstellar extinction over the cluster area is uniform and
normal with E(B-V)=0.51±0.03mag. We determine a distance of
3.3±0.23Kpc to the cluster. The theoretical isochrone fittings to
the Cepheid variables as well as the evolved part of the main-sequence
near turn-off point indicate that the cluster is 120±20Myr old. We
estimate the cluster radius to be 3.7' using radial stellar density
profile. Both the distance and age determined using period
luminosity/age relations for the Cepheid variables are consistent
with their membership of the cluster. This unique opportunity has
therefore been used to refine the zero-point of the period-luminosity
relation for the Galactic Cepheids.
Objects:
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RA (2000) DE Designation(s)
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23 58 24 +61 13.0 NGC 7790 = C 2355+609
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 67 1156 Relative (X, Y) pixel positions and CCD BVI
magnitudes of stars measured in the field of
NGC 7790 are presented.
table1.tex 82 1272 LaTeX version of table 1
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See also:
V/28 : Proper motions and UBV phot. in 4 open clusters (Frolov 1980)
J/PASP/104/553 : CCD Standard Fields (Odewahn+ 1992)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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2- 5 I4 --- Seq Sequential number (1)
7- 12 F6.2 pix Xpos X position (2)
14- 19 F6.2 pix Ypos Y position (2)
21- 26 F6.3 mag Vmag V magnitude
28- 33 F6.3 mag B-V ? B-V colour index
35- 40 F6.3 mag V-I V-I Cousins colour index
42- 68 A27 --- Names Other identifications, separated by commas (3)
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Note (1): Numbers are the same as Phelps & Janes (1994ApJS...90...31P 1994ApJS...90...31P)
Numbers staring from 5001 is new detection of stars in this cluster
Note (2): The coordinate system is that of the database given by Phelps & Janes
(1994ApJS...90...31P 1994ApJS...90...31P). The center of the cluster is located at
RA = 23h 54min 12s, DE = +60° 57' (1950.0)
1 pix = 0.74". North is up, and east is to the left.
Note (3): Other identifications:
F: Frolov, 1977IzPul.195...80F 1977IzPul.195...80F, Cat. V/28
I: Iyeshima et al., 1994, Ann. Rep. Nishi - Harima Astron. Obs. 4, 18
O: Odewahn et al., 1992PASP..104..553O 1992PASP..104..553O, Cat. J/PASP/104/553
P: Pedreros et al., 1984ApJ...286..563P 1984ApJ...286..563P
R: Romeo et al., 1989MNRAS.240..459R 1989MNRAS.240..459R
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Acknowledgements: Alok Chandra Gupta
(End) Patricia Bauer [CDS] 05-Dec-2000