High resolution radio observations of the Chamaeleon star-forming region

TL;DR

This study uses radio observations to detect and analyze young stars in the Chamaeleon star-forming region, revealing their emission mechanisms, binary nature, and providing precise positions for future mass measurements.

Contribution

First detailed radio survey of the Chamaeleon region identifying multiple young stars and confirming non-thermal emission mechanisms, including the detection of a binary system.

Findings

Detected five young stars definitively and five tentatively.

Confirmed non-thermal radio emission in most sources.

Identified a binary system with a ~40-year orbital period.

Abstract

We report on large-scale radio observations of the Chamaeleon star-forming region obtained with the Australia Telescope Compact Array (ATCA) that led to the definite detection of five young stars and the tentative detection of five more. As in other regions surveyed in the radio domain, the majority of detected sources are fairly evolved low-mass T Tauri stars, but we also detect one protostellar object (Ced 110 IRS4) and one Herbig Ae/Be star. With the exception of the protostellar source, the radio emission mechanism is likely of non-thermal origin. The three brightest radio stars identified with ATCA were subsequently observed with the Australian Long Baseline Array (LBA) and one, J11061540-7721567 (Ced 110 IRS2), was detected at three epochs. This confirms the non-thermal nature of the radio emission in that specific case, and enabled accurate radio position measurements. Comparison with predictions from Gaia DR3 strongly suggests that this star is a binary system with an orbital period of order 40 years; additional LBA observations in the next decades would enable accurate determinations of the individual stellar masses in that system.