Teff and log g dependence of velocity fields in M-stars
Abstract
We present an investigation of velocity fields in early to late M-type hydrodynamic stellar atmosphere models. These velocities will be expressed in classical terms of micro- and macro-turbulent velocities for usage in 1D spectral synthesis. The M-star model parameters range between log g of 3.0-5.0 and Teff of 2500 K-4000 K. We characterize the Teff- and log g-dependence of the hydrodynamical velocity fields in these models with a binning method, and for the determination of micro-turbulent velocities, the Curve of Growth method is used. The macro-turbulent velocities are obtained by convolutions with Gaussian profiles. Velocity fields in M-stars strongly depend on log g and Teff. Their velocity amplitudes increase with decreasing log g and increasing Teff. The 3D hydrodynamical and 1D macro-turbulent velocities range from ~100 m/s for cool high gravity models to ~800 m/s-1000 m/s for hot models or models with low log g. The micro-turbulent velocities range in the order of ~100 m/s for cool models, to ~600 m/s for hot or low log g models. Our M-star structure models are calculated with the 3D radiative-hydrodynamics (RHD) code CO5BOLD. The spectral synthesis on these models is performed with the line synthesis code LINFOR3D.
- Publication:
-
Recent Directions in Astrophysical Quantitative Spectroscopy and Radiation Hydrodynamics
- Pub Date:
- September 2009
- DOI:
- 10.1063/1.3250073
- arXiv:
- arXiv:0908.0820
- Bibcode:
- 2009AIPC.1171..323W
- Keywords:
-
- radiative transfer;
- magnetohydrodynamics;
- stellar atmospheres;
- 95.30.Jx;
- 95.30.Qd;
- 97.10.Ex;
- Radiative transfer;
- scattering;
- Magnetohydrodynamics and plasmas;
- Stellar atmospheres;
- radiative transfer;
- opacity and line formation;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- 8 pages, 6 Figures, Proceeding fot the "Recent directions in astrophysical quantitative spectroscopy and radiation hydrodynamics" conference