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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
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); 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). Objects: ----------------------------------------- RA (2000) DE Designation(s) ----------------------------------------- 17 24.7 -49 57 IC 4651 ----------------------------------------- File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table3.dat 118 387 uvbyHβ photometry in IC 4651 (V ≤ 15)
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
Bytes Format Units Label Explanations
1- 3 I3 --- Number ? Number in IC 4651 6- 8 I3 --- Eggen ? Eggen number (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
Note (1): The common system defined for IC 4651 in the galactic open cluster WebDa data compilation ( 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.
History: From AJ electronic edition
(End) Greg Schwarz [AAS] 22-May-2000
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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