Young Double Stars in the Chamaeleon Clouds

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Session 40 -- Young Stars and T Tauri Stars
Display presentation, Thursday, January 13, 9:30-6:45, Salons I/II Room (Crystal Gateway)

[40.03] Young Double Stars in the Chamaeleon Clouds

W.P.Chen, H.C.Fan (NCU), J.A.Graham (DTM)

Young stars in the Chamaeleon~I and II dark clouds have been surveyed for duplicity by direct imaging in near infrared. We present lists of stars that show either extended structure or a neighboring star within 20". In Cha~I, 15 of the 67 association members observed are found to have at least one neighboring star within 1-5", a fraction significantly higher than that in Taurus, which is at a similar distance, in the same separation range. Cha~I also shows a high incidence rate of wide systems. Cha~II cloud, with a much smaller sample, shows a similar fraction (5 out of 19) of systems less than 5" but appears to relatively lack of wide pairs. Lines of sight to Chamaeleon are more likely to be confused by galactic background stars than to Taurus. After excluding companions against background contamination, as judged from their brightness, color, and the local surface number density of stars, a frequency of 10\% is deduced for 2--5" binaries, which is comparable to that in Taurus and to that of main sequence field stars. Near-infrared photometry and thus colors of the surveyed sample and of the components of each pair will be presented.

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