A Radio Survey of Older T Tauri Stars
in the $\eta $ Chamaeleontis Cluster

Eric E. Mamajek , Warrick A. Lawson , Eric D. Feigelson, PASA, 16 (3), 257.
Next Section: Introduction
Contents Page: Volume 16, Number 3

A Radio Survey of Older T Tauri Stars
in the $\eta $ Chamaeleontis Cluster

Eric E. Mamajek 1,2
Warrick A. Lawson 1
Eric D. Feigelson 3

1 School of Physics, University College UNSW, Australian Defence Force Academy,
Canberra ACT 2600, Australia.
eem, wal@ph.adfa.edu.au

2 J. William Fulbright Fellow

3 Department of Astronomy & Astrophysics, Pennsylvania State University, University Park,
PA 16802, USA.


A radio continuum survey of X-ray-identified weak-lined T Tauri stars (WTTs) in the newly-discovered $\eta $ 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 $\approx$8 Myr and masses ranging from 0.1-1.0 M$_{\odot}$. Our survey detected none of the 10 X-ray-emitting WTTs with 3$\sigma\,$ 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 they are not, as a group, fast-rotating stars. The non-detection in radio 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, moreso than youth, appears to be the key to radio-emission in young stars.

Keywords: URL:

open clusters and associations: $\eta $ Chamaeleontis - stars: pre-main-sequence
radio continuum: stars.

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