Звездный ветер и эффективность плазменного радиоизлучения экзопланет

Письма в Астрономический журнал. 2024. Т. 50. № 1. С. 100–109.

Зайцев В. В., Shaposhnikov V., Ходаченко М. Л., Руменских М. С.

We present the results of our study of the influence of stellar activity on the efficiency of the plasma radio emission generation mechanism and the properties of this emission in the atmospheres of exoplanets with a weak magnetic field. The plasma generation mechanism can be efficiently realized in the case where the Langmuir frequency exceeds the electron gyrofrequency, and the electron cyclotron maser is inefficient. This mechanism, which depends significantly on plasma parameters, suggests the generation of plasma (quasi-static) waves by energetic electrons followed by their conversion into electromagnetic radiation. The stellar wind, depending on its intensity, can modify significantly the plasmasphere of an exoplanet and change its parameters. Using the interaction of the exoplanet HD 189733b with a stellar wind of various intensities from the central star as an example, we show that the plasma mechanism can be realized at any stellar wind intensity, only the requirements for the parameters of the plasma mechanism change. In particular, the plasmawave energy density needed to generate a radio flux accessible to detection by modern radio-astronomical means changes, and its frequency range changes. The latter will allow the detected radio emission to be used as an indicator of the activity of the parent star.

Keywords: радиоизлучение, экзопланеты, звездный ветер, плазменный механизм генерации