As the number of observed brown dwarf outflows is growing it is important to
investigate how these outflows compare to the well studied jets from young
stellar objects. A key point of comparison is the relationship between outflow
and accretion activity and in particular the ratio between the mass outflow and
accretion rates (M˙out/M˙acc). The brown dwarf candidate
ISO-ChaI 217 was discovered by our group, as part of a spectro-astrometric
study of brown dwarfs, to be driving an asymmetric outflow with the
blue-shifted lobe having a position angle of ∼ 20∘. The aim here
is to further investigate the properties of ISO-ChaI 217, the morphology and
kinematics of its outflow, and to better constrain
(M˙out/M˙acc). The outflow is spatially resolved in the
[SII]λλ6716,6731 lines and is detected out to ∼ 1\farcs6
in the blue-shifted lobe and ~ 1" in the red-shifted lobe. The asymmetry
between the two lobes is confirmed although the velocity asymmetry is less
pronounced with respect to our previous study. Using thirteen different
accretion tracers we measure log(M˙acc) [Msun/yr]= -10.6 ±
0.4. As it was not possible to measure the effect of extinction on the ISO-ChaI
217 outflow M˙out was derived for a range of values of Av, up to
a value of Av = 2.5 mag estimated for the source extinction. The logarithm
of the mass outflow (M˙out) was estimated in the range -11.7 to -11.1
for both jets combined. Thus M˙out/M˙acc [\Msun/yr] lies
below the maximum value predicted by magneto-centrifugal jet launching models.
Finally, both model fitting of the Balmer decrements and spectro-astrometric
analysis of the Hα line show that the bulk of the H I emission comes
from the accretion flow.Comment: accepted by Astronomy & Astrophysic