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تسجيل مستخدم جديدM-dwarfs Chromosphere, Corona and Wind Connection via the Nonlinear Alfven Wave
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M dwarfs atmosphere is expected to be highly magnetized. The magnetic energy can be responsible for heating the stellar chromosphere and corona, and driving the stellar wind. The nonlinear propagation of Alfven wave is the promising mechanism for both heating stellar atmosphere and driving stellar wind. Based on this Alfven wave scenario, we carried out the one-dimensional compressive magnetohydrodynamic (MHD) simulation to reproduce the stellar atmospheres and winds of TRAPPIST-1, Proxima Centauri, YZ CMi, AD Leo, AX Mic, as well as the Sun. The nonlinear propagation of Alfven wave from the stellar photosphere to chromosphere, corona, and interplanetary space is directly resolved in our study. The simulation result particularly shows that the slow shock generated through the nonlinear mode coupling of Alfven wave is crucially involved in both dynamics of stellar chromosphere (stellar spicule) and stellar wind acceleration. Our parameter survey further revealed the following general trends of physical quantities of stellar atmosphere and wind. (1) The M dwarfs coronae tend to be cooler and denser than solar corona. (2) M dwarfs stellar winds can be characterized with relatively faster velocity and much smaller mass-loss rate compared to those of solar wind. The physical mechanisms behind these tendencies are clarified in this paper, where the stronger stratification of M dwarfs atmosphere and relatively smaller Alfven wave energy input from the M dwarfs photosphere are remarkable.
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M dwarfs atmosphere and wind is expected to be highly magnetized. The nonlinear propagation of Alfven wave could play a key role in both heating the stellar atmosphere and driving the stellar wind. Along this Alfven wave scenario, we carried out the
one-dimensional compressive magnetohydrodynamic (MHD) simulation about the nonlinear propagation of Alfven wave from the M dwarfs photosphere, chromosphere to the corona and interplanetary space. Based on the simulation results, we develop the semi-empirical method describing the solar and M dwarfs coronal temperature, stellar wind velocity, and winds mass loss rate. We find that M dwarfs coronae tend to be cooler than solar corona, and that M dwarfs stellar winds would be characterized with faster velocity and much smaller mass loss rate compared to those of the solar wind.
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