The Relationship between Accretion and Ionised Ejection among Young Stellar Objects in the Coronet Cluster

TL;DR

This study investigates the link between mass accretion and ionised outflows in young stellar objects, revealing a consistent sublinear correlation and evolutionary changes in jet efficiency, with implications for star formation models.

Contribution

It extends the understanding of accretion-ejection connection to earlier YSO stages using multi-epoch observations and detailed flux measurements.

Findings

Sublinear correlation between ionised mass-loss and accretion rates.

Modest variability observed with no clear short-term correlation.

Increase in jet efficiency ratio from class I to class II YSOs.

Abstract

We present results from a coordinated, multi-epoch near-infrared and centimeter radio survey of young stellar objects (YSOs) in the Coronet, aimed at probing the connection between mass accretion and ionised mass loss. Using VLT-KMOS, we detect Br$\gamma$ emission in 5 of the 26 targets, which also exhibit 3.3-cm continuum emission in VLA images, consistent with partially ionised jets. For seven additional sources, stringent flux upper limits were obtained. The derived accretion and ionised mass-loss rates for class I and class II YSOs follow a sublinear correlation $\dot{M}_{\mathrm{ion}} \propto \dot{M}_{\mathrm{acc}}^{0.3}$, consistent with previous results for class II YSOs but extended here to earlier stages. Multi-epoch observations reveal modest variability in both tracers but no clear temporal correlation between accretion and ejection within timescales of a few months. The ratio $\dot{M}_{\mathrm{ion}}/\dot{M}_{\mathrm{acc}}$ shows an anti-correlation with $\dot{M}_{\mathrm{acc}}$, increasing with time from class I YSOs to class II YSOs, suggesting an increase in jet-launching efficiency or ionisation fraction with evolution. These findings support a direct connection between accretion and outflow across the $\sim$ Myr timescale of YSO evolution, while highlighting the complexity of their short-term interplay.