J/AJ/113/1723 UBVI photometry in 4 open clusters (Kassis+, 1997)
Deep CCD photometry of old open clusters.
Kassis M., Janes K.A., Friel E.D., Phelps R.L.
<Astron. J., 113, 1723-1732 (1997)>
=1997AJ....113.1723K 1997AJ....113.1723K
ADC_Keywords: Clusters, open ; Photometry, UBV ; Photometry, UBVRI
Abstract:
Ages and distance moduli for the open clusters NGC 2204, Berkeley 39,
NGC 2477, and Melotte 66 are constrained by comparing the theoretical
models developed by Bertelli et al. (1994, Cat. J/A+AS/106/275) to the
observed cluster color-magnitude diagrams which are based on deep CCD
photometry. Out of a set of comparison models, no single isochrone was
superior to the others in describing an observed color-magnitude
diagram. Thus, a best fitting model was selected based not only on the
match to an observed color-magnitude diagram, but also on the
isochrone's agreement with adopted values for the cluster's
metallicity and reddening. The range of otherwise acceptable models
help quantify the age and distance modulus uncertainty of each
cluster. Based on the best fitting models:
* NGC 2204 is 1.6+0.9-0.3Gyr old with (m-M)o=13.0+0.5-0.4 ,
* Berkeley 39 has an age of 6+2-1Gyr with (m-M)o=12.9±0.2,
* NGC 2477 is 1+0.3-0.2Gyr old with (m-M)o=10.5+0.4^-0.3 , and
* Melotte 66 has an age of 4±1Gyr with (m-M)o=13.2+0.3-0.1.
Description:
Deep photometry for the open clusters NGC 2204, NGC 2477, Berkeley 39,
and Melotte 66 was obtained during a 5-night observing program at the
1.5m telescope at Cerro Tololo Inter American Observatory, 1994 April.
Abundances and distances adopted:
NGC 2204 [Fe/H]=-0.35±0.08 E(B-V)=0.13±0.04 D=4kpc Age=1.6Gyr
Berkeley 39 [Fe/H]=-0.31±0.08 E(B-V)=0.11±0.09 D=3.8kpc Age=6Gyr
NGC 2477 [Fe/H]=-0.05±0.11 E(B-V)=0.2 to 0.4 D=1.3kpc Age=1Gyr
Melotte 66 [Fe/H]=-0.51±0.11 E(B-V)=0.14 to 0.21 D=4.4kpc Age=4Gyr
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
n2204vi.dat 60 2468 VI photometry in NGC 2204
n2477vi.dat 60 8529 VI photometry in NGC 2477
be39vi.dat 60 4014 VI photometry in Berkeley 39
mel66vi.dat 60 3727 VI photometry in Melotte 66
n2204bvi.dat 90 2035 BVI photometry in NGC 2204
n2477bvi.dat 90 6360 UBVI photometry in NGC 2477
be39bvi.dat 90 3181 UBVI photometry in Berkeley 39
--------------------------------------------------------------------------------
Byte-by-byte Description of file: mel66vi.dat n2204vi.dat be39vi.dat n2477vi.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
2- 5 I4 --- Seq Star number in cluster
8- 14 F7.2 pix Xpos X-position on CCD
17- 23 F7.2 pix Ypos Y-position on CCD
25- 30 F6.3 mag Vmag [8/24.1] V-band magnitude (Landolt system)
32- 37 F6.3 mag V-I I-band magnitude (Landolt system)
39- 43 F5.3 mag e_Vmag Error on Vmag
45- 49 F5.3 mag e_V-I Error on (V-I)
51- 54 F4.2 --- dP [0/2.9]
57 I1 --- nV [1/4] Number of V-band observations
60 I1 --- nI [1/3] Number of I-band observations
--------------------------------------------------------------------------------
Byte-by-byte Description of file: be39bvi.dat n2204bvi.dat n2477bvi.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
2- 5 I4 --- Seq Star number in cluster
7- 13 F7.2 pix Xpos X-position on CCD
15- 21 F7.2 pix Ypos Y-position on CCD
23- 28 F6.3 mag Vmag [8/24.1] V-band magnitude (Landolt system)
30- 35 F6.3 mag B-V (B-V) color index (Landolt system)
37- 42 F6.3 mag U-B ?=99.999 (U-B) color index (Landolt system)
44- 49 F6.3 mag V-I ?=99.999 (V-I) color index (Landolt system)
51- 55 F5.3 mag e_Vmag Error on Vmag
57- 61 F5.3 mag e_B-V Error on (B-B)
63- 67 F5.3 mag e_U-B Error on (U-B)
69- 73 F5.3 mag e_V-I Error on (V-I)
75- 78 F4.2 --- dP [0/2.9]
81 I1 --- nV [1/4] Number of V-band observations
84 I1 --- nB [1/3] Number of I-band observations
87 I1 --- nU [0/3] Number of I-band observations
90 I1 --- nI [0/3] Number of I-band observations
--------------------------------------------------------------------------------
History:
From Webda, http://www.univie.ac.at/webda/archive_ngc.html
(End) Patricia Vannier, Francois Ochsenbein [CDS] 11-Jan-2008