Spatially resolved atomic and molecular emission from the very low-mass star IRS54

TL;DR

This study spatially resolves molecular and atomic emissions from the outflow of the very low-mass star IRS54, revealing complex structures and higher accretion rates compared to similar objects, indicating its youth.

Contribution

First spatially resolved imaging of molecular and atomic emissions around a very low-mass star, revealing detailed outflow structures and accretion characteristics.

Findings

Complex outflow cavity and asymmetric jet structure identified.

Atomic jet counterpart discovered extending to the source.

High Lacc/Lbol ratio (~80%) indicating a very young object.

Abstract

Molecular outflows from very low-mass stars (VLMSs) and brown dwarfs (BDs) have been studied very little, and only a few objects have been directly imaged. Using VLT SINFONI K-band observations, we spatially resolved, for the first time, the H2 emission around IRS54, a ~0.1-0.2 Msun Class I source. The molecular emission shows a complex structure delineating a large outflow cavity and an asymmetric molecular jet. In addition, new [FeII] VLT ISAAC observations at 1.644um allowed us to discover the atomic jet counterpart which extends down to the central source. The outflow structure is similar to those found in low-mass Class I young stellar objects (YSOs) and Classical TTauri stars (CTTSs). However, its Lacc/Lbol ratio is very high (~80%), and the derived mass accretion rate is about one order of magnitude higher than in objects with similar mass, pointing to the young nature of the investigated source.