Astronomy and Astrophysics – Astrophysics – Solar and Stellar Astrophysics
Scientific paper
2011-06-20
Astronomy and Astrophysics
Astrophysics
Solar and Stellar Astrophysics
20 pages, 4 figures, accepted by ApJ Letters
Scientific paper
We present the first pilot study of jets from young stars conducted with X-shooter, on ESO/VLT. As it offers simultaneous, high quality spectra in the range 300-2500 nm X-shooter is uniquely important for spectral diagnostics in jet studies. We chose to probe the accretion/ejection mechanisms at low stellar masses examining two targets with well resolved continuous jets lying on the plane of the sky, ESO-HA 574 in Chamaleon I, and Par-Lup3-4 in Lupus III. The mass of the latter is close to the sub-stellar boundary (Mstar=0.13 Msun). A large number of emission lines probing regions of different excitation are identified, position-velocity diagrams are presented and mass outflow/accretion rates are estimated. Comparison between the two objects is striking. ESO-HA 574 is a weakly accreting star for which we estimate a mass accretion rate of log(\dot{Macc}) = -10.8 \pm 0.5 (in Msun/yr), yet it drives a powerful jet with \dot{Mout} ~ 1.5-2.7 10^-9 Msun/yr. These values can be reconciled with a magneto-centrifugal jet acceleration mechanism only assuming that the presence of the edge-on disk severely depresses the luminosity of the accretion tracers. In comparison Par-Lup3-4 with stronger mass accretion (log(\dot{Macc}) = -9.1 \pm 0.4 Msun/yr), drives a low excitation jet with about \dot{Mout} ~ 3.2 10^-10 Msun/yr in both lobes. Despite the low stellar mass, \dot{Mout} / \dot{Macc} for Par-Lup3-4 is at the upper limit of the range usually measured for young objects, but still compatible with a steady magneto-centrifugal wind scenario if all uncertainties are considered.
Alcala' Juan M.
Bacciotti Francesca
Cupani Guido
Nisini Brunella
Podio Linda
No associations
LandOfFree
The First X-shooter Observations of Jets from Young Stars does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The First X-shooter Observations of Jets from Young Stars, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The First X-shooter Observations of Jets from Young Stars will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-254976