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Paper: Chamaeleon
Volume: 5, Handbook of Star Forming Regions:
Volume II, The Southern Sky
Page: 169
Authors: Luhman, K.L.
Abstract: The dark clouds in the constellation of Chamaeleon have distances of 160-180 pc from the Sun and a total mass of ∼5000 M. The three main clouds, Cha I, II, and III, have angular sizes of a few square degrees and maximum extinctions of AV ∼ 5-10. Most of the star formation in these clouds is occurring in Cha I, with the remainder in Cha II. The current census of Cha I contains 237 known members, 33 of which have spectral types indicative of brown dwarfs (>M6). Approximately 50 members of Cha II have been identified, including a few brown dwarfs. When interpreted with the evolutionary models of Chabrier and Baraffe, the H-R diagram for Cha I exhibits a median age of ∼2 Myr, making it coeval with IC 348 and slightly older than Taurus (∼1Myr). The IMF of Cha I reaches a maximum at a mass of 0.1-0.15 M, and thus closely resembles the IMFs in IC 348 and the Orion Nebula Cluster. The disk fraction in Cha I is roughly constant at ∼ 50% from 0.01 to 0.3 M and increases to ∼ 65% at higher masses. In comparison, IC 348 has a similar disk fraction at low masses but a much lower disk fraction at M ≥ 1 M, indicating that solar-type stars have longer disk lifetimes in Cha I.
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