In addition to the five-minute acoustic oscillations of the Sun, much longer-pe-riod oscillations were predicted to exist in the Sun more than forty years ago but had not been identified. Our team recently observed these global oscilla-tions with very long periods, comparable to the 27-day solar rotation period. The oscillations manifest themselves at the solar surface as very slow swirling motions with speeds on the order of 1 m/s. These motions were measured by analysing ten years of observations from NASA’s Solar Dynamics Observa-tory. Using computer models, we find that the newly discovered oscillations are resonant modes and owe their existence to the Sun’s differential rotation. Some modes of oscillation have maximum velocity near the poles, some at mid-latitudes, and some near the equator. Taken all together, the Sun's inertial modes will help establish novel ways to probe the solar interior and obtain in-formation about our star’s inner structure and dynamics.
Date: Wednesday December 1, 2021 - 17:00 CEST (online)
https://unigraz.webex.com/meet/manuela.temmer