CDROM/AJ/V106/P0181 M67 (Montgomery+ 1993) ================================================================================ CCD Photometry of the Old Open Cluster M67 Kent A. Montgomery, Laurence A. Marschall, & Kenneth A. Janes <1993, AJ, 106, 181> =1993AJ....106..181M ================================================================================ Abstract: We present a CCD photometric survey of the central one-half degree of the old open cluster, M67, in U, B, V, and I colors to magnitude V=20. Extensive comparison of our photometry with other published datasets shows excellent agreement, indicating that CCD photometry is capable of producing a uniform set of measurements consistent with the photometric system defined primarily by the Landolt standard sequence. The color-magnitude diagram of the cluster shows a well-defined main sequence extending at least to the limit of the photometry at M(V)=10.55 and a substantial binary sequence. At least 38% of cluster stars are binaries. The current generation of theoretical isochrones cannot be fit to the observed sequences within the observational errors. We find a tendency for more massive members of the cluster to be more centrally concentrated, along with a turnover in the cluster luminosity function at low masses, which may be due to dynamical relaxation of the cluster. To the limit of our photometry, we find a mass of the cluster of 724 solar masses. In addition, we present a sample of stars of well-determined standard magnitudes that are suitable as photometric standards for further studies of this cluster and for general calibration of the UBVI photometry using CCDs. File Summary: -------------------------------------------------------------------------------- File Name Lrecl Records Explanations -------------------------------------------------------------------------------- table3.dat 136 1456 Photometry -------------------------------------------------------------------------------- Comments for file: table3.dat -------------------------------------------------------------------------------- Table 3 contains all Montgomery et al. (1993) stars as well as stars brighter than 12th magnitude from previously published data. MMJ star numbers followed by an asterisk correspond to stars which fall on the photometric binary sequence in the color-magnitude diagram. MMJ star numbers enclosed in parentheses indicate stars with a V magnitude brighter than 12; their photometry is compiled from previously published sources. The last eighteen characters correspond to cross referencing. The first number corresponds to Sanders (1977, A&AS, 27, 89), numbers preceded with a roman numeral are from Eggen & Sandage (1964, ApJ, 140, 130), numbers preceded with an F are from Fagerholm (1906, Inaugural dissertation, Uppsala), numbers preceded with a G refer to Gilliland et al. (1991, AJ, 101, 541). The sources of photometry of stars brighter than 12th magnitude are enclosed in parentheses in the comments (to match the MMJ star number) as given in Table 4 of the printed paper: (ES) for Eggen & Sandage (1964), (JS) for Janes & Smith (1984, AJ, 89, 487), (G) for Gilliland et al. (1991), (M) for Murray et al. (1965, Roy. Obs. Bull., No. 91), and (S) for Sanders (1989, RMxA, 17, 31). -------------------------------------------------------------------------------- Byte-by-byte Description of file: table3.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1 1X --- Lpar [(] Left parenthesis, see comments 2- 5 I4 --- MMJ MMJ star number 6 A1 --- Rpar [)*] Asterisk or right paren, see comments 7 1X --- --- Blank 8- 10 F3.0 h RAh Right ascension (1950) 11- 13 F3.0 min RAm R.A. 14- 19 F6.2 s RAs R.A. 20 1X --- --- Blank 21 A1 --- DE- Sign of declination (always blank) 22- 23 F2.0 deg DEd Declination (1950) 24- 26 F3.0 arcmin DEm Dec. 27- 31 F5.1 arcsec DEs Dec. 32- 38 F7.3 mag V V magnitude 39- 45 F7.3 mag B-V B-V color 46- 52 F7.3 mag U-B []? U-B color 53- 59 F7.3 mag V-R []? V-R color 60- 66 F7.3 mag V-I []? V-I color 67- 72 F6.3 mag e_V V error 73- 78 F6.3 mag e_B-V B-V error 79- 84 F6.3 mag e_U-B U-B error 85- 90 F6.3 mag e_V-R V-R error 91- 96 F6.3 mag e_V-I V-I error 97-101 F5.2 arcsec e_RADE positional error 102-104 I3 --- n_V Number of V obs 105-107 I3 --- n_B Number of B obs 108-110 I3 --- n_U Number of U obs 111-113 I3 --- n_R Number of R obs 114-116 I3 --- n_I Number of I obs 117-118 2X --- --- Blank 119-136 A18 --- Comment Comments (see description above) -------------------------------------------------------------------------------- ================================================================================ (End) Lee Brotzman [ADS] 08-Mar-1995