J/AJ/119/2282 Stromgren photometry of IC 4651 (Anthony-Twarog+, 2000)
CCD uvbyHβ photometry in clusters. I. The open cluster standard, IC 4651
Anthony-Twarog B.J., Twarog B. A.
<Astron. J. 119, 2282 (2000)>
=2000AJ....119.2282A 2000AJ....119.2282A
ADC_Keywords: Clusters, open ; HR diagrams ; Photometry, uvby, beta
Keywords: color-magnitude diagrams - open clusters and associations:
individual (IC 4651)
Abstract:
CCD photometry of the intermediate-age open cluster IC 4651 on the
uvbyHβ system is presented and analyzed. By using a combination
of the information from the color-magnitude diagram (CMD) and the
color-color diagrams, a sample of 98 highly probable main-sequence
cluster members with high photometric accuracy is isolated.
Description:
Photoelectric photometry of IC 4651 on the uvbyHβ system obtained
on the 0.9 and 1.5 m telescopes at the Cerro Tololo Inter-American
Observatory (CTIO) between 1982 and 1985 was presented in
Anthony-Twarog & Twarog (1987AJ.....94.1222A 1987AJ.....94.1222A); this photometry was
then used to calibrate a set of small-format CCD frames to further
define the structure of the cluster at faint magnitudes. The
photoelectric observations had been transformed to the standard system
using the traditional technique of defining nightly calibration curves
based upon standard star observations made on each night. The standard
system adopted for those transformations was based upon local
secondary uvby standards near the south Galactic pole (SGP) compiled
by Twarog (1984AJ.....89..523T 1984AJ.....89..523T).
Objects:
-----------------------------------------
RA (2000) DE Designation(s)
-----------------------------------------
17 24.7 -49 57 IC 4651
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 118 387 uvbyHβ photometry in IC 4651 (V ≤ 15)
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See also:
J/A+AS/140/135 : Stromgren Photometry in NGC 3680 and NGC 6134 (Bruntt+, 1999)
J/AJ/125/1383 : Stromgren photometry of NGC 6253 (Anthony-twarog+, 2003)
J/AJ/127/1000 : Stromgren photometry of NGC 3680 (Anthony-twarog+, 2004)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Number ? Number in IC 4651
6- 8 I3 --- Eggen ? Eggen number (1971ApJ...166...87E 1971ApJ...166...87E)
11- 16 F6.1 pix Xpix X coordinate (1)
20- 25 F6.1 pix Ypix Y coordinate (1)
28- 33 F6.3 mag Vmag V band magnitude from literature
37- 41 F5.3 mag (b-y) Stromgren (b-y) color
44- 49 F6.3 mag m1 ? Stromgren (v-b)-(b-y) magnitude
50 A1 --- u_m1 [:] Indicates an uncertain m1 measurement
52- 57 F6.3 mag c1 ? Stromgren (u-v)-(v-b) magnitude
58 A1 --- u_c1 Indicates an uncertain c1 measurement
61- 65 F5.3 mag beta ? Stromgren Hβ index (2)
69- 73 F5.3 mag e_Vmag Uncertainty in Vmag
77- 81 F5.3 mag e_(b-y) Uncertainty in (b-y)
85- 89 F5.3 mag e_m1 ? Uncertainty in m1
93- 97 F5.3 mag e_c1 ? Uncertainty in c1
101-105 F5.3 mag e_beta ? Uncertainty in Beta
108 I1 --- Ny [,7[ Number of y frames used
110 I1 --- Nb [,7[ Number of b frames used
112 I1 --- Nv [,3[ Number of v frames used
114 I1 --- Nu [,3[ Number of u frames used
116 I1 --- NHbetaW [,9[ Number of wide Hβ frames used
118 I1 --- NHbetaN [,8[ Number of narrow Hβ frames used
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Note (1): The common system defined for IC 4651 in the galactic open cluster
WebDa data compilation (http://obswww.unige.ch/webda/information.html)
The scale of the coordinate system, centered on Eggen 56, is
∼ 3.2''/unit.
Note (2): beta = 2.5*log((Hβwide)/(Hβnarrow)) where the half-
widths of Hβwide and Hβnarrow are 150 and 30 Å
respectively.
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History:
From AJ electronic edition
(End) Greg Schwarz [AAS] 22-May-2000