![]() Σ x and σ y are the standard deviations for the populations Where r is the correlation coefficient between the populations x and y.Ĭov(x,y) is the covariance between populations. We calculated these correlations by the Pearson’s correlation coefficient (Bobko 2001) from the next formula as follows: (1) r = c o v x, y σ x σ y (1) The conclusions are presented in Section 5.įirst, we examined the correlation coefficients between the V-band observations and the previous studies for M67. The statistical comparisons methods and discussions between our BV magnitudes and the published photometric data are described in Section 4. The membership, photometric, and physical parameters are explained in Section 3. Observations and CCD calibration data are presented in Section 2. We determined the distance (astrometry) of the cluster using high-quality parallax from the Gaia EDR3 and three CMDs (photometry). We used three CMDs of the Gaia EDR3 and the BV CCD observations of the KFISP. We used the statistical comparisons between our observations and the available data from the literature to test the quality and deviations from the published literature. Determination of physical parameters of the standard open cluster M67 using the high-quality of the astrometry from the latest version of the Gaia telescope, Gaia EDR3, and the BV observations taken from the KFISP. This work aims to test the quality of the observations from the Kottamia Faint Imaging Spectro-Polarimeter (KFISP) of the 74-inch telescope, Egypt. The photometric limit of the passbands used (G, G BP, G RP) of the Gaia EDR3, corresponding photometric errors, and completeness is in a high-quality better than Gaia DR2. For sources G < 20 mag the photometric uncertainties are 6, 108, 52 mmag of G, G BP, and G RP respectively (Gaia Collaboration et al. For sources G < 17 mag the photometric uncertainties are 1, 12, 6 mmag of G, G BP, and G RP respectively. For Gaia EDR3, sources with G < 13 mag the photometric uncertainties are 0.3, 0.9, 0.6 mmag of G, G BP, and G RP respectively. For sources G < 20 mag the photometric uncertainties are 10, 200, 200 mmag of G, G BP, and G RP respectively (Gaia Collaboration et al. For sources G < 17 mag the photometric uncertainties are 2, 10, 10 mmag of G, G BP, and G RP respectively. ( 2021) by using the surveys of both GALactic Archaeology with HERMES (GALAH) and the Apache Point Observatory Galactic Evolution Experiment (APOGEE) determined the log(age) = 9.63 yr, distance is 882 ± 42 pc, π ˉ = 1.14 ± 0.05 mas, and μ α c o s δ ‾, μ α ‾ = − 10.99 ± 0.21, − 2.96 ± 0.22 mas/yr.įor Gaia DR2, sources with G < 13 mag the photometric uncertainties are 0.3, 2, 2 mmag of G, G BP and G RP respectively. 2016) estimated the cluster age is 4.00 Gyr. ( 2011) found the radial velocity (RV) of the cluster M67 is RV = 33.74 ± 0.12 km/s, velocity dispersion is 0.54 and 0.68 km/s for giants and dwarfs, respectively, which in both cases is substantially lower than reported in previous works. 1986, 1990 Milone 1992, Milone and Latham 1994) calculated the radial velocities. 2015) calculated membership probability using a fitting model consisting of normal frequency functions on Vector Point Diagram (VPD). The equatorial coordinates of the M67 are RA = 08 h 51 m 18 s.00 and DEC = +11° 48 ′ 00 ″.00, the Galactic coordinates are l = 215°.6961 and b = +31°.8963, and the angular diameter is 25 arcmin (Dias et al. 2014) search for exoplanet candidates inside this cluster. 2009) investigated variable stars inside the cluster. 2002 Sandquist and Shetrone 2003a, 2003b Stello et al. The old open cluster M67 (NGC 2682) has been the topic of many studies in the last 40 years. ![]() Open star clusters are the basis to understand stellar evolution.
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