EDP Sciences
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Volume 440, Number 3, September IV 2005
Page(s) 1119 - 1126
Section Stellar structure and evolution
DOI http://dx.doi.org/10.1051/0004-6361:20053037

A&A 440, 1119-1126 (2005)
DOI: 10.1051/0004-6361:20053037

Mass loss at the lowest stellar masses

M. Fernández1, 2 and F. Comerón3

1  Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
    e-mail: matilde@mpia-hd.mpg.de
2  Instituto de Astrofísica de Andalucía, CSIC, Camino Bajo de Huétor 50, 18008 Granada, Spain
3  European Southern Observatory, Karl-Schwarzschild-Strasse 2, 85748 Garching, Germany
    e-mail: fcomeron@eso.org

(Received 10 March 2005 / Accepted 9 June 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 $\ga$8$^{\circ}$) with respect to the plane of the sky. The width of the H$_{\alpha}$ line suggests a dominating contribution from the accretion columns and from the shocks on the stellar surface. Unresolved H$_{\alpha}$ emission coming from an object located at 4$\farcs$2 from Par-Lup3-4 is detected at a position angle ~30$^{\circ}$ or ~210$^{\circ}$, 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.

Key words: stars: individual: Par-Lup3-4 -- stars: individual: LS RCrA-1 -- stars: low-mass, brown dwarfs -- stars: pre-main sequence -- ISM: jets and outflows

SIMBAD Objects

© ESO 2005