SIMBAD references

Context. 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 [OI]_63µm and [OI]_145µm transitions. Spectroscopic [OI]_63µm maps enabled us to infer the spatial extent of warm (T∼500-1200K), low-excitation atomic gas within these protostellar outflows.
Aims. Our main goal is to determine mass-loss rates from the obtained [OI]_63µm maps and compare these with accretion rates from other studies.
Methods. The far-infrared [OI]_63µm emission line is predicted to be the main coolant of dense, dissociative J-shocks caused by decelerated wind or jet shocks. If proper shock conditions prevail, the instantaneous mass-ejection rate is directly connected to the [OI]_63µm luminosity. In order to unravel evolutionary trends, we analysed a set of 14 Class 0/I outflow sources that were spatially resolved in the [OI]₆₃ 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 [OI]_63µm line.
Results. All our newly observed targets feature prominent [OI]_63µm emission either close to the driving source (L1551 IRS5, HH 1, HH 212) or as extended jet-like or knotty emission region away from it (Cep E). The detected [OI]_63µm emission can mostly be attributed to dissociative shocks and photodissociation regions (PDRs). Flux values at 63µm and 145µm of all four associated continuum sources are presented. We calculated mass-loss rates connected to the low-excitation, atomic outflow component in the range of (5-50)x10^–7M_☉/yr. Estimated ratios between the mass loss in the outflow and the mass accretion onto the source (jet efficiency ratios) are largely in the range of M_out/M_acc∼0.05-0.5 for the observed outflow sources, which are consistent with theoretical predictions and quoted Herschel data.
Conclusions. Our new observations and a comparison with the 72 outflow sources observed with Herschel indicate that the bulk ejected material in outflows from Class 0 sources resides in the molecular component, that is mass-loss rates derived from the [OI]₆₃ emission line significantly underestimate the total mass-loss rate during this and possibly also later phases of the star formation process.