CDROM/AJ/V106/P0220 Be 31 (Guetter 1993) ================================================================================ Photometric Study of the Old Galactic Cluster Be 31 Harry H. Guetter <1993, AJ, 106, 220> =1993AJ....106..220G ================================================================================ Abstract: CCD photometry on the Johnson UBV and on the Kron-Cousins VI systems are presented for 732 stars in and near Be 31, an open cluster located towards the galactic anticenter. The resultant color-magnitude diagrams indicate that the cluster is an old object. From the color-color diagram, the reddening and metallicity parameters are determined to be E(B-V) = 0.13 mag and [Fe/H] = -0.4. By comparing the cluster C-M diagrams with the VandenBerg isochrones, and by assuming a normal reddening law, a distance of 5.2 +/- 0.5 kpc and an age of 8 Gyr are derived. File Summary: -------------------------------------------------------------------------------- File Name Lrecl Records Explanations -------------------------------------------------------------------------------- table1.dat 42 732 Observational data -------------------------------------------------------------------------------- Comments for file: table1.dat -------------------------------------------------------------------------------- Be 31 (OCl 513, 1950 R.A. = 06:54.9, Dec. = +08:20, l = 206.3 deg, b = 5.1 deg) is an open cluster located toward the direction of the galactic anticenter. The detector was a TI 800x800 thinned CCD which was UV flooded. The detector-telescope combination provides a field of view of 5.7x5.7 arcmin, which corresponds to a pixel size of 0.43 arcsec. In the pixel coordinates described below, the top left or northeast corner is (1,1) and the bottom right is (800,800). The instrumental magnitudes and colors were transformed linearly to the Johnson and Kron-Cousins system by using measures of 16 Landolt standards (1983) in seven fields. The mean errors in converting the instrumental magnitude system to the standard systems were 0.012, 0.019, 0.012 and 0.012 mag for (V-I), V, (B-V), and (U-B), respectively. -------------------------------------------------------------------------------- Byte-by-byte Description of file: table1.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1 I3 --- Star Star number 4-10 F7.2 mag V V magnitude 11-16 F6.2 mag B-V []? B-V color 17-22 F6.2 mag U-B []? U-B color 23-28 F6.2 mag V-I []? V-I color 29-35 F7.1 pixel X X coordinate 36-42 F7.1 pixel Y Y coordinate -------------------------------------------------------------------------------- ================================================================================ (End) Lee Brotzman [ADS] 08-Mar-1995