Red giants in open clusters VII . Melotte 71 ? , ? ?
نویسندگان
چکیده
New CORAVEL radial-velocity observations and UBV photometry of 24 red giants in the field of the intermediate-age open cluster Mel 71 are analysed for membership and duplicity. The membership of 16 stars is confirmed, one star is a possible member, and 8 spectroscopic binaries have been discovered , all amongst the cluster stars. Four of their orbits have been determined, with periods ranging from 74 to 1627 days. The mean cluster velocity is +50.14 ± 0.14 (s.e.) km s −1 , and the binary frequency is unusually high (8/16 = 50%). The best isochrone fit to the observed colour-magnitude digram is obtained for logt = 9.00 and Z = 0.008. However, some discrepancies appear between the observed and predicted locations of the red giant clump.
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