All Figures

$\begin{figure} \par\includegraphics[height=8.4cm,width=5.1cm,clip]{5484fig1.ps}\end{figure}$ Figure 1: Density contours in the poloidal plane of an accretion-ejection structure where a viscous and resistive MHD disc is launching a collimated jet. Magnetic field lines are drawn in black solid lines, while the fast magnetosonic surface corresponds to the white solid line (Alfvèn surface is the black dotted line). The size of the sink region is $R_{\rm i}=0.1~ {\rm AU}$ and the stellar mass is $1~ M_{\odot}$ .
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In the text

$\begin{figure} \par\includegraphics[height=4.9cm,width=6.6cm,clip]{5484fig2.eps}\end{figure}$ Figure 2: Temporal evolution of several angular momentum fluxes occurring inside the accretion-ejection structure displayed in Fig. 1. The various fluxes are normalized to the amount of angular momentum removed from the disc $L_{\rm MEC}$ . The dominant way to remove disc angular momentum is provided by the magnetic torque leading to the creation of a jet.
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In the text

$\begin{figure} \par\includegraphics[height=8.4cm,width=4.9cm,clip]{5484fig3.ps}\end{figure}$ Figure 3: Same as in Fig. 1 but with a ideal stellar wind emitted from the inner region whose ejection mass rate is $\dot{M} = 10^{-9}~ M_{\odot}/$ yr. The disc-driven jet conserves a very similar dynamical structure to the case where no stellar wind is emitted. The size of the sink region is $R_{\rm i}=0.1~ {\rm AU}$ and the stellar mass is $1~ M_{\odot}$ .
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In the text

$\begin{figure} \par\includegraphics[height=8.4cm,width=3.6cm,clip]{5484F4_1.ps}\... ...F4_3.ps}\includegraphics[height=8.4cm,width=3.6cm,clip]{5484F4_4.ps}\end{figure}$ Figure 4: Time evolution of a two-component jet launched from a thin accretion disc threaded by a bipolar magnetic field. The outflow is composed of a disc-driven jet embedding a non-ideal stellar wind emitted from a YSO located at the center of the simulation in the sink region. The density contours are represented by greyscales while poloidal magnetic field lines are displayed using solid lines. The various snapshots represent the same system but at different stages (after five, ten, twenty, and thirty inner disc rotations).The simulation was performed with a stellar mass-loss rate of $\dot{M} = 10^{-9}~ M_{\odot}/$ yr. In the early stages of our simulation the stellar wind is the only outflow of the system while as the simulation goes on, a disc-driven jet appears around the stellar outflow and collimates it. The size of the sink region is $R_{\rm i}=0.1~ {\rm AU}$ and the stellar mass is $1~ M_{\odot}$ .
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In the text

$\begin{figure} \par\includegraphics[height=10.2cm,width=5.8cm,clip]{5484F5_1.ps}... ...*{4mm} \includegraphics[height=10.2cm,width=5.8cm,clip]{5484F5_2.ps}\end{figure}$ Figure 5: Left: plot of the initial temperature isocontours of the accretion disc. Right: plot of the temperature isocontours of the simulation displayed in Fig. 3. Temperature isocontours are not displayed in the external medium (outside of both the jet, stellar wind, and disc) as it is considered a near vacuum medium with very low temperature. The size of the sink region is $R_{\rm i}=0.1~ {\rm AU}$ and the stellar mass is $1~ M_{\odot}$ .
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In the text

$\begin{figure} \par\includegraphics[height=4.8cm,width=6.6cm,clip]{5484Fig6.ps}\end{figure}$ Figure 6: Plot of the vertical variation at $R=1~{\rm AU}$ from the axis of the temperature in the simulation displayed in Fig. 5. The size of the sink region is $R_{\rm i}=0.1~ {\rm AU}$ and the stellar mass is $1~ M_{\odot}$ .
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In the text

$\begin{figure} \par\includegraphics[height=4.9cm,width=16.1cm,clip]{5484Fig7.ps}\end{figure}$ Figure 7: a) Plot of the ejection mass rate from the accretion disc. b) The inner accretion rate. c) The ratio of the stellar mass-loss rate to the disc-wind mass-loss rate as a function of time. These plots are related to the simulation performed with a stellar mass loss of $\dot{M} = 10^{-9}~ M_{\odot}/$ yr.
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In the text

$\begin{figure} \par\includegraphics[height=6.5cm,width=7.7cm,clip]{5484F8R.eps}\... ...e*{6mm} \includegraphics[height=6.5cm,width=7.6cm,clip]{5484F8L.eps}\end{figure}$ Figure 8: Plot of the various forces Left: along a given magnetic field line anchored in the accretion disc, Right: along a streamline anchored to the stellar corona. These plots show the various forces accelerating the flow: $f_{\rm C}^{\rm s}$ is the centrifugal force, $f_{\rm M}^{\rm s}$ the magnetic one, $f_{\rm P}^{\rm s}$ the pressure gradient, and $f_{\rm G}^{\rm s}$ the gravitational force.
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In the text

$\begin{figure} \par\includegraphics[height=6.8cm,width=7.9cm,clip]{5484F9.eps}\end{figure}$ Figure 9: Plot of the transverse forces as a function of R at a given altitude Z = 75. It shows, across a given cross section of the jet, the collimation processes acting in the stellar and disc components of the jet for the simulation with a stellar mass loss $M_\odot=10^{-9}~M_\odot/$ yr. $f_{\rm C}^{\rm n}$ is the centrifugal force, $f_{\rm P}^{\rm n}$ the pressure gradient and $f_{\rm G}^{\rm n}$ the gravitational force. $f_{M_\theta }^{\rm n}$ the Lorentz force due to the toroidal component of the magnetic field, while $f_{M_{\rm P}}^{\rm n}$ corresponds to the poloidal component.
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In the text

$\begin{figure} \par\includegraphics[height=6.4cm,width=7.2cm,clip]{5484F10.eps}\end{figure}$ Figure 10: The vertical variations of specific energies, normalized to the maximum kinetic energy flux, along a streamline in the stellar wind with a rate $\dot{M} = 10^{-9}~ M_{\odot}/$ yr. This plot clearly illustrates the thermal acceleration provided by the enthalpy to the stellar wind material. The enthalpy gradient is here sustained by local turbulent Ohmic heating representing, in our simulation, $35\%$ of the energy released by accretion (see Sect. 3.2.2).
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In the text

$\begin{figure} \par\includegraphics[height=6.6cm,width=8cm,clip]{5484F11L.eps}\h... ...*{3mm} \includegraphics[height=6.6cm,width=7.9cm,clip]{5484F11R.eps}\end{figure}$ Figure 11: Same plots as in Fig. 8 but for a simulation where the stellar mass ejection rate is $\dot{M} = 10^{-7}~ M_{\odot}/$ yr.
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In the text

$\begin{figure} \par\includegraphics[height=8.7cm,width=7.4cm,clip]{5484F12.ps}\end{figure}$ Figure 12: Same density plot as in Fig. 3 but for a smaller zone around the sink. The three critical surfaces are represented by dark lines (slow-magnetosonic), dashed lines (Alfvèn), and white lines (fast-magnetsonic). The size of the sink region is $R_{\rm i}=0.1~ {\rm AU}$ and the stellar mass is $1~ M_{\odot}$ . The sink region is represented by a black square in the center.
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In the text

$\begin{figure} \par\includegraphics[height=4.4cm,width=5.8cm,clip]{5484F13L.ps}\... ...*{10mm} \includegraphics[height=4.4cm,width=5.8cm,clip]{5484F13R.ps}\end{figure}$ Figure 13: The transverse variation of the vertical velocity at Z = 8 AU, for the simulation with stellar mass loss $\dot{M} = 10^{-9}~ M_{\odot}/$ yr, $M_*=M_{\odot }$ , and R_I=0.1 AU, Left: without any non-ideal effects in the stellar wind but with a large amount of thermal energy deposited at the base of the stellar outflow ( $\delta _{\varepsilon }=10^{-3}$ ). Right: with turbulent viscosity and resistivity in the stellar wind and a small amount of thermal energy at the base ( $\delta _{\varepsilon }=10^{-5}$ ). The turbulence allows a better thermal stellar mass acceleration as velocity becomes higer near the polar axis.
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In the text

$\begin{figure} \par\includegraphics[height=11.2cm,width=6.5cm,clip]{5484F14.ps}\end{figure}$ Figure 14: Same figure as in Fig. 1 but with a non-ideal stellar wind emitted from the inner region with an ejection mass rate $\dot{M} = 10^{-7}~ M_{\odot}/$ yr. The outflow structure is substantially modified by the presence of the stellar outflow since its radial extension is two times larger than in the case with no, or weak, stellar outflow. The size of the sink region is $R_{\rm i}=0.1~ {\rm AU}$ and the stellar mass $1~ M_{\odot}$ .
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In the text

$\begin{figure} \par\includegraphics[height=3.7cm,width=14.3cm,clip]{5484F15.ps}\end{figure}$ Figure 15: Plot of the temporal evolution of the ejection mass-loss rate from the accretion disc in a) the ratio of the stellar mass-loss rate to the ejection mass-loss rate from the accretion disc as a function of time in b) for the simulation with a stellar mass-loss rate of $\dot{M} = 10^{-7}~ M_{\odot}/$ yr.
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In the text

$\begin{figure} \par\includegraphics[height=4.9cm,width=15.9cm,clip]{5484F16.eps}\end{figure}$ Figure 16: The transverse variation of different physical quantities as magnetic-field components, velocity components, and the fast-magnetosonic Mach number at Z = 100, for the simulation with stellar mass loss $\dot{M} = 10^{-7}~ M_{\odot}/$ yr.
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In the text

$\begin{figure} \par\includegraphics[height=4.9cm,width=6.6cm,clip]{5484fig2.eps}\end{figure}$	Figure 2: Temporal evolution of several angular momentum fluxes occurring inside the accretion-ejection structure displayed in Fig. 1. The various fluxes are normalized to the amount of angular momentum removed from the disc $L_{\rm MEC}$ . The dominant way to remove disc angular momentum is provided by the magnetic torque leading to the creation of a jet.
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$\begin{figure} \par\includegraphics[height=8.4cm,width=4.9cm,clip]{5484fig3.ps}\end{figure}$	Figure 3: Same as in Fig. 1 but with a ideal stellar wind emitted from the inner region whose ejection mass rate is $\dot{M} = 10^{-9}~ M_{\odot}/$ yr. The disc-driven jet conserves a very similar dynamical structure to the case where no stellar wind is emitted. The size of the sink region is $R_{\rm i}=0.1~ {\rm AU}$ and the stellar mass is $1~ M_{\odot}$ .
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$\begin{figure} \par\includegraphics[height=4.8cm,width=6.6cm,clip]{5484Fig6.ps}\end{figure}$	Figure 6: Plot of the vertical variation at $R=1~{\rm AU}$ from the axis of the temperature in the simulation displayed in Fig. 5. The size of the sink region is $R_{\rm i}=0.1~ {\rm AU}$ and the stellar mass is $1~ M_{\odot}$ .
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$\begin{figure} \par\includegraphics[height=4.9cm,width=16.1cm,clip]{5484Fig7.ps}\end{figure}$	Figure 7: a) Plot of the ejection mass rate from the accretion disc. b) The inner accretion rate. c) The ratio of the stellar mass-loss rate to the disc-wind mass-loss rate as a function of time. These plots are related to the simulation performed with a stellar mass loss of $\dot{M} = 10^{-9}~ M_{\odot}/$ yr.
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$\begin{figure} \par\includegraphics[height=6.6cm,width=8cm,clip]{5484F11L.eps}\h... ...*{3mm} \includegraphics[height=6.6cm,width=7.9cm,clip]{5484F11R.eps}\end{figure}$	Figure 11: Same plots as in Fig. 8 but for a simulation where the stellar mass ejection rate is $\dot{M} = 10^{-7}~ M_{\odot}/$ yr.
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$\begin{figure} \par\includegraphics[height=8.7cm,width=7.4cm,clip]{5484F12.ps}\end{figure}$	Figure 12: Same density plot as in Fig. 3 but for a smaller zone around the sink. The three critical surfaces are represented by dark lines (slow-magnetosonic), dashed lines (Alfvèn), and white lines (fast-magnetsonic). The size of the sink region is $R_{\rm i}=0.1~ {\rm AU}$ and the stellar mass is $1~ M_{\odot}$ . The sink region is represented by a black square in the center.
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$\begin{figure} \par\includegraphics[height=3.7cm,width=14.3cm,clip]{5484F15.ps}\end{figure}$	Figure 15: Plot of the temporal evolution of the ejection mass-loss rate from the accretion disc in a) the ratio of the stellar mass-loss rate to the ejection mass-loss rate from the accretion disc as a function of time in b) for the simulation with a stellar mass-loss rate of $\dot{M} = 10^{-7}~ M_{\odot}/$ yr.
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$\begin{figure} \par\includegraphics[height=4.9cm,width=15.9cm,clip]{5484F16.eps}\end{figure}$	Figure 16: The transverse variation of different physical quantities as magnetic-field components, velocity components, and the fast-magnetosonic Mach number at Z = 100, for the simulation with stellar mass loss $\dot{M} = 10^{-7}~ M_{\odot}/$ yr.
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