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| Paper: |
Evolution from Coronal Wind to Structured Chromospheric Wind |
| Volume: |
472, New Quests in Stellar Astrophysics III: A Panchromatic View of Solar-like Stars, With and Without Planets |
| Page: |
247 |
| Authors: |
Suzuki, T. K. |
| Abstract: |
In this article, I introduce our results on the evolution of
the stellar wind from low-mass stars with surface convective
layers, following Suzuki (2007).
By performing magnetohydrodynamical simulations from the
photospheres to a few tens of stellar radii, we study
the dynamics and energetics of the stellar winds.
The main process in driving the stellar winds is nonlinear dissipation
of Alfvénic waves excited from the surface convection zones.
When the stellar radius becomes ∼ 10 times that of the Sun, the steady hot
corona with temperature 106 K, suddenly disappears because the atmospheric
material streams out before heated up to the the coronal temperature.
Instead, many hot and warm (105 – 106 K) bubbles form in
cool (T < 2 × 104 K) chromospheric winds
because of the thermal instability of the radiative cooling function;
the red giant wind is not a steady stream but structured outflow. |
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