Investigation of the Praesepe cluster ⋆
نویسندگان
چکیده
Coravel observations of 103 F5-K0 stars in the Praesepe cluster yielded 24 spectroscopic binaries (3 are non-members), and 20 orbits were determined, with periods from 4 to 7400 days. Based on a complete sample in the colour range 0.40 ≤ B − V ≥ 0.80 (80 stars, including KW 244 = TX Cnc), the companion star fraction CSF = 0.45. The percentage of spectroscopic binaries with P < 1000. d is 20% (16/80). The combined photometric and spectroscopic analysis showed that 12 among 18 single-lined spectroscopic binaries are located within the " single " star sequence in the (V, B − V) diagram and cannot be detected by the photometric analysis in the UBV system. In addition, seven photometrically analysed bi-naries were not detected with the radial velocity observations, but are confirmed members. The number of single:binary:triple stars is 47:30:3.
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