Type‐III Solar Radio Bursts at Mars: A 16.5‐Year Catalog From Mars Express‐MARSIS at 0.1–5.5 MHz

The most intense radio feature in the Solar System are the solar Type‐III radio bursts, which are associated with electron beams that propagate along open magnetic field lines. Although solar radio bursts have been studied since the 1940s, observations remain mainly restricted within 1 AU. In this study, we explore 16.5 years of data (2005–2021) from the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) onboard Mars Express. While not the central aim of the instrument, MARSIS has been recording solar radio bursts since its deployment in mid‐2005. Given the potential of this new radio burst data set for heliophysics studies, we have created a catalog of Type‐III solar radio burst events between 1.38 and 1.66 AU (Mars' orbit) within the frequency range of 0.1 and 5.5 MHz and with an instrument measuring cadence of 7.5 s. We demonstrate that these emissions seen at Mars come from the Sun, follow the solar cycle pattern, and are not influenced by the planet's own properties such as crustal magnetic fields. We also compare the propagation of a few illustrative events from the Sun to Mars to demonstrate the utility of this new data set for heliophysics studies. Mars catalogs provide a fundamentally new perspective on the spatial extent, directivity, and evolution of solar radio emission in the inner heliosphere. It serves as an essential benchmark for multi‐point heliospheric studies and for constraining radio emissions mechanisms beyond Earth orbit, and demonstrating the usefulness of planetary missions in contributing to heliophysics science in diverse ways.