Evolution of the atomic component in protostellar outflows

TL;DR

This study uses far-infrared observations to analyze atomic gas in protostellar outflows, revealing spatial structures and evolutionary trends by comparing multiple sources across different classes.

Contribution

It provides the first spatially resolved [O I]63mum maps of several protostellar outflows, linking atomic emission to outflow evolution and mass-ejection rates.

Findings

Spatial extent of atomic gas varies among outflows.

[O I]63mum luminosity correlates with mass-ejection rate.

Evolutionary trends observed across Class 0 and I sources.

Abstract

We present SOFIA/FIFI-LS observations of three Class 0 and one Class I outflows (Cep E, HH 1, HH 212, and L1551 IRS5) in the far-infrared [O I]63mum and [O I]145mum transitions. Spectroscopic [O I]63mum maps enabled us to infer the spatial extent of warm, low-excitation atomic gas within these protostellar outflows. If proper shock conditions prevail, the instantaneous mass-ejection rate is directly connected to the [O I]63mum luminosity. In order to unravel evolutionary trends, we analysed a set of 14 Class 0/I outflow sources that were spatially resolved in the [O I]63mum emission. We compared these data with a sample of 72 Class 0/I/II outflow sources that have been observed with Herschel (WISH, DIGIT, WILL, GASPS surveys) without spatially resolving the [O I]63mum line.