The small-scale HH34 IRS jet as seen by X-shooter

Abstract

Very little information has been so far gathered on atomic jets from young embedded low mass sources (class I stars), especially in the inner jet region. We exploit multiwave spectroscopic observations to infer physical conditions of the inner region of HH34 IRS, a prototypical class I jet. We use a deep X-shooter spectrum ( lambda = 350-2300 nm, R between 8000 and 18000) detecting lines with upper energies from 8000 to 31000 cm-1 . Statistical equilibrium and ionization models are adopted to derive the jet main physical parameters. We derive the physical conditions for the extended high velocity jet (HVC, V about -100 km/s) and for the low velocity and compact gas (LVC, V about -20-50 \kms). At the jet base (< 200 AU) the HVC is mostly neutral (x(e)< 0.1) and very dense (n(H) > 5x10^5 cm-3). The LVC gas has the same density and A_V as the HVC, but it is a factor of two colder. Iron abundance in the HVC is close to solar, while it is 3 times subsolar in the LVC, suggesting an origin of the LVC gas from a dusty disk. We infer a jet mass flux rate > 5x10^{-7} Mo/yr. We find that the relationships between accretion luminosity and line luminosity derived for T Tauri stars cannot be directly extended to class I sources surrounded by reflection nebulae since the permitted lines are seen through scattered light. An accretion rate of about 7\,10^{-6} Mo/yr is instead derived from an empirical relationship connecting the mass accretion rate with L([OI])(HVC). In conclusion, the HH34 IRS jet shares many properties with jets from active CTTs stars. It is however denser as a consequence of the larger mass flux rate. These findings suggest that the acceleration and excitation mechanisms in jets are not influenced by evolution and are similar in CTTs and in still embedded and highly accreting sources.

arXiv comment18 pages, 10 figure, Accepted on Astronomy & Astrophysics

References in corpus (35)

• X-shooter, the new wide band intermediate resolution spectrograph at the ESO Very Large Telescope
• X-Shooter spectroscopy of young stellar objects: IV -- Accretion in low-mass stars and sub-stellar objects in Lupus
• UV excess measures of accretion onto young very low-mass stars and brown dwarfs
• Which jet launching mechanism(s) in TTauri stars?
• Launching of Conical Winds and Axial Jets from the Disk-Magnetosphere Boundary: Axisymmetric and 3D Simulations
• The solar chemical composition
• A combined optical/infrared spectral diagnostic analysis of the HH1 jet
• Recipes for stellar jets: results of combined optical/infrared diagnostics
• Measuring Protoplanetary Disk Accretion with H I Pf-beta
• Collimation, Proper Motions, and Physical Conditions in the HH 30 Jet From HST Slitless Spectroscopy
• X-Shooter spectroscopy of young stellar objects: V - Slow winds in T Tauri stars
• Fluid Dynamics of Stellar Jets in Real Time: Third Epoch HST Images of HH 1, HH 34, and HH 47
• The outflow history of two Herbig-Haro jets in RCW 36: HH 1042 and HH 1043
• Accretion and ejection properties of embedded protostars: the case of HH26, HH34 and HH46 IRS
• Probing stellar accretion with mid-infrared hydrogen lines
• The First X-shooter Observations of Jets from Young Stars
• Subaru IR Echelle Spectroscopy of Herbig-Haro Driving Sources I. H_2 and [Fe II] Emission
• HST/STIS observations of the RW Aurigae bipolar jet: mapping the physical parameters close to the source
• IR diagnostics of embedded jets: velocity resolved observations of the HH34 and HH1 jets
• POISSON project - III - Investigating the evolution of the mass accretion rate
• Physical properties of the jet from DG Tauri on sub-arcsecond scales with HST/STIS
• IR diagnostics of embedded jets: kinematics and physical characteristics of the HH46-47 jet
• X-ray emission from protostellar jet HH 154: the first evidence of a diamond shock?
• The diagnostic potential of Fe lines applied to protostellar jets
• Physical Structure and Dust Reprocessing in a sample of HH Jets
• Multi-epoch Sub-arcsecond [Fe II] Spectroimaging of the DG Tau Outflows with NIFS. I. First data epoch
• ESO-H$\alpha$~574 and Par-Lup3-4 Jets: Exploring the spectral, kinematical and physical properties
• HST FUV imaging of DG Tau: Fluorescent molecular hydrogen emission from the wide angle outflow
• The Structure of the Inner HH 34 Jet from Optical Integral Field Spectroscopy
• Empirical determination of Einstein A-coefficient ratios of bright [Fe II] lines
• Very low-luminosity Class I/Flat outflow sources in sigma Orionis
• The jet/counterjet IR symmetry of HH34 and the size of the jet formation region
• AO Assisted Near-IR Spectroscopy of SVS 13 and its Jet
• Uncertainties in Atomic Data and Their Propagation Through Spectral Models. I
• The HH34 outflow as seen in [FeII]1.64um by LBT-LUCI

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