Query : 2010A&A...511A...5G

2010A&A...511A...5G - Astronomy and Astrophysics, volume 511, A5-5 (2010/2-2)

IR diagnostics of embedded jets: kinematics and physical characteristics of the HH46-47 jet.


Abstract (from CDS):

We present an analysis of the kinematics and physical properties of the Class I driven jet HH46-47 based on IR medium and low resolution spectroscopy obtained with ISAAC on VLT. Our aim is to study the gas physics as a function of the velocity and distance from the source and to compare the results with similar studies performed on other Class I and classical T Tauri jets as well as with existing models for the jet formation and excitation. The ratios and luminosities of several important diagnostic lines (e.g. [FeII]1.644, 1.600µm, [PII]1.189µm, and H2 lines) have been used to derive physical parameters such as electron density, H2 temperature, iron gas-phase abundance and mass flux. [FeII]1.644µm and H22.122µm position velocity diagrams (PVDs) have been additionally constructed to study the kinematics of both the atomic and molecular gas. Within 1000-2000AU from the source the atomic gas presents a wide range of radial velocities, from ~-230km/s to ∼100km/s. Only the gas component at the highest velocity (high velocity component, HVC) survives at large distances. The H2 shows only a single velocity component at almost zero velocity close to the source while it reaches higer velocities (up to ∼95km/s) further downstream. Electron densities (ne) and mass ejection fluxes ({dot}(M)jet) have been separately measured for the HVC and for the component at lower velocity (LVC) from the [FeII] lines. ne increases with decreasing velocities with an average value of ∼6000cm–3 for the LVC and ∼4000cm–3 for the HVC, while the opposite occurs for {dot}(M)jet which is ∼0.5-2x10–7M/yr and ∼0.5-3.6x10–8M/yr for the HVC and LVC, respectively. The mass flux carried out by the molecular component, measured from the H2 lines flux, is ∼4x10–9M/yr. We have estimated that the Fe gas phase abundance is significantly lower than the solar value, with ∼88% of iron still depleted onto dust grains in the internal jet region. This fraction decreases to ∼58%, in the external knots. Many of the derived properties of the HH46-47 jet are common to jets from young stellar objects (YSOs) in different evolutionary states. The derived densities and mass flux values are typical of Class I objects or very active T Tauri stars. However, the spatial extent of the LVC and the velocity dependence of the electron density have been so far observed only in another Class I jet, the HH34 jet, and are not explained by the current models of jet launching.

Abstract Copyright:

Journal keyword(s): circumstellar matter - Herbig-Haro objects - ISM: jets and outflows - ISM: individual objects: HH46-47 - infrared: ISM

Nomenclature: Fig. 1: [EM94] AN (Nos Y1-Y3, Z1-Z2) added.

Simbad objects: 5

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Number of rows : 5
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
1 HH 34 HH 05 35 31.30 -06 28 43.0     16     ~ 483 2
2 HH 1 HH 05 36 20.8 -06 45 13           ~ 408 1
3 HH 111 HH 05 51 44.2 +02 48 34           ~ 404 0
4 NAME HH 46-47 HH 08 25 43.6 -51 00 36           ~ 197 2
5 2MASS J08254384-5100326 Y*O 08 25 43.85 -51 00 32.7           ~ 313 1

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