A Radio Survey of Older T Tauri Stars in the rj Chamaeleontis Cluster

: A radio continuum survey of X-ray-identified weak-lined T Tauri stars (WTTs) in the newly-discovered r] Chamaeleontis cluster has been completed using the Australia Telescope Compact Array (ATCA). The 10 known WTTs in the cluster form a unique sample of codistant late-type pre-main-sequence stars with ages of ~8 Myr and masses ranging from 0-1—1-0 MQ. Our survey detected none of the 10 X-ray-emitting WTTs with 3cr sensitivity limits at 4–8 and 8–6 GHz (6–2 and 3–5 cm) of typically 0–4 mJy, corresponding to a radio luminosity of 4–5 x 1015 erg Hz-1 s-1. Rotation periods for these stars indicate that they are not, as a group, fast-rotating stars. The non-detection in the radio bands supports the findings of other radio surveys of inhomogeneous samples of young stars, where radio emission is fairly common (10-30%) among very young T Tauri stars across all late spectral types, but confined to rapidly-rotating F-G-K stars amongst older zero-age main sequence stars. Rotation, more than youth, appears to be the key to radio emission in young stars.