STEHLÉ , Chantal

The aim of the project (ANR STARSHOCK) is to understand the dynamics and the radiative properties of accretion columns, linking the circumstellar disk to the surface photosphere of Young Stellar Objects. The hydrodynamics is computed first, using a high resolution hydrodynamic 1D ALE code (AS-TROLABE) coupled to radiative transfer and line...

Theory and simulations predict Quasi-Periodic Oscillations of shocks which develop in magnetically driven accretion funnels connecting the stellar disc to the pho-tosphere of Young Stellar Objects (YSO). X-ray observations however do not show evidence of the expected periodicity. We examine here, in a first attempt, the influence of radiative...

We present preliminary results of radiative properties of a 1D gray radiation hydrodynamic (RHD) model of an accretion shock on a young stellar object (YSO). This model takes into account the transition between the collisional equilibrium regime (local thermodynamic equilibrium, LTE), and the coronal equilibrium regime. Based on the 1D planar...

We address the problem of the contribution of radiation to the structure and dynamics of accretion shocks on Young Stellar Objects. Solving the 3D RTE (radiative transfer equation) under our "gray LTE approach", i.e., using appropriate mean opacities computed in local thermodynamic equilibrium, we post-process the 3D MHD (magne-tohydrodynamic)...

The dynamics of YSO accretion shocks is determined by radiative processes as well as the strength and structure of the magnetic field. A quasi-periodic emission signature is theoretically expected to be observed, but observations do not confirm any such pattern. In this work, we assume a uniform background field, in the regime of optically thin...

The structure and dynamics of young stellar object (YSO) accretion shocks depend strongly on the local magnetic field strength and configuration, as well as on the radiative transfer effects responsible for the energy losses. We present the first 3D YSO shock simulations of the interior of the stream, assuming a uniform background magnetic...