Star-Planet Interactions in the Radio Domain: Prospect for Their Detection

TL;DR

This paper reviews the potential for detecting star-planet interactions through radio emissions, discussing theoretical models, known solar system examples, and recent observational advances with new low-frequency radio telescopes.

Contribution

It provides a comprehensive analysis of radio signatures from star-planet interactions, integrating theoretical frameworks and recent observational data to guide future detections.

Findings

Radio signatures can reveal magnetic field properties of exoplanets.

The radio-magnetic scaling law estimates the power of star-planet radio emissions.

Recent low-frequency radio telescopes have begun detecting potential star-planet radio signals.

Abstract

All types of interaction of a magnetized plasma flow with an obstacle (magnetized or not) are considered, and those susceptible to produce a radio signature are identified. The role of the sub-Alfv\'enic or super-Alfv\'enic character of the flow is discussed. Known examples in the solar system are given, as well as extrapolations to star-planet plasma interactions. The dissipated power and the fraction that goes into radio waves are evaluated in the frame of the radio-magnetic scaling law, the theoretical bases and validity of which are discussed in the light of recent works. Then it is shown how radio signatures can be interpreted in the frame of the cyclotron-maser theory (developed for explaining the generation of solar system planetary auroral and satellite-induced radio emissions) for deducing many physical parameters of the system studied, including the planetary or stellar magnetic field. Recent detections of such radio signatures with new generation low-frequency radiotelescopes and future prospects are then outlined.