Key points are not available for this paper at this time.
Two hundred forty-two members of the Praesepe and α Persei clusters have been surveyed with high angular resolution 2.2 μm speckle imaging on the 3 m Infrared Telescope Facility, the 5 m Hale, and the 10 m Keck telescopes, along with direct imaging using the near-infrared camera (NICMOS) aboard the Hubble Space Telescope . The observed stars range in spectral type from B (∼5 M ⊙ ) to early M (∼0.5 M ⊙ ), with the majority of the targets more massive than ∼0.8 M ⊙ . The one quadruple and 39 binary systems detected encompass separations from 0 053 to 7 28; 28 of the systems are new detections, and there are nine candidate substellar companions. The results of the survey are used to test binary star formation and evolution scenarios and to investigate the effects of companion stars on X-ray emission and stellar rotation. The main results are as follows:
Patience et al. (Fri,) studied this question.