Mass loss at the lowest stellar masses

Fernández, M. and Comerón, F.
Astronomy and Astrophysics, Volume 440, Issue 3, September IV 2005, pp.1119-1126 (2005).


We report the discovery of a jet in a [SII] image of Par-Lup3-4, a remarkable M 5-type pre-main sequence object in the Lupus 3 star-forming cloud. The spectrum of this star is dominated by the emission lines commonly interpreted as tracers of accretion and outflows. Par-Lup3-4 is therefore at the very low-mass end of the exciting sources of jets. High resolution spectroscopy shows that the [SII] line profile is double-peaked, implying that the low excitation jet is seen at a small angle (probably ⪆8circ) with respect to the plane of the sky. The width of the Hα line suggests a dominating contribution from the accretion columns and from the shocks on the stellar surface. Unresolved Hα emission coming from an object located at 4farcs2 from Par-Lup3-4 is detected at a position angle 30circ or 210circ, with no counterpart seen either in visible or infrared images. We also confirm previous evidence of strong mass loss from the very low mass star LS-RCrA 1, with spectral type M 6.5 or later. All its forbidden lines are blueshifted with respect to the local standard of rest (LSR) of the molecular cloud at a position very close to the object and the line profile of the [OI] lines is clearly asymmetric. Thus, the receding jet could be hidden by a disk which is not seen edge-on. If an edge-on disk does not surround Par-Lup3-4 or LS-RCrA 1, an alternative explanation, possibly based on the effects of mass accretion, is required to account for their unusually low luminosities.