Magnetic activity nesting on the Sun and low-mass stars: Results from nearly continuous monitoring of solar active nests with ESA’s Solar Orbiter

Recording: https://www.oact.inaf.it/seminars/

DATE: Thursday, January 22, 11:30 a.m.

ORGANIZER: INAF-OACT

LOCATION: AULA OVEST (INAF-OACT) + remote

Link for the remote audience:
https://meet.google.com/wvf-uwxo-oyj

SPEAKER: Adam Finley (ESA Noordwijk)

ABSTRACT:
The magnetic activity of low-mass stars, driven by the interplay of convection and rotation in their interiors, is fundamental to their evolution and significantly affects the search for habitable exoplanets. Magnetic activity manifests at the surface as “spots” (or active regions) that influence the circumstellar environment through energetic radiation and eruptive events (flares and coronal mass-ejections, collectively termed “space weather”). The Sun exhibits a well-known 11-year activity cycle where spot emergence drifts from mid to low latitudes. However, one puzzling feature of the solar dynamo is the repeated emergence of spots in close proximity, which leads to long-lived sources of magnetic activity known as active nests. Nesting is observed on other low-mass stars, suggesting it is an innate, universal feature of stellar dynamos. It is theorized that non-axisymmetries in the generation and storage of the magnetic field preference the emergence of spots at specific latitudes and longitudes, leading to nesting. This phenomenon has consequences for predicting space weather near Earth and understanding the secular evolution of exoplanetary atmospheres. Studies of solar active nests have been limited by our single viewpoint from Earth. But with ESA’s Solar Orbiter now monitoring the Sun’s far-side for several months each year, multi-viewpoint observations provide a pathway to study the formation and evolution of active nests. So far we have identified an active nest in 2022 that was responsible for 50–70% of all solar flares across the entire solar surface over five months (a prolific flare factory). In addition, we saw a dramatic intensification of solar flare activity in 2024 following the collision of two active nests. These continuous, multi-viewpoint observations strengthen the connection between solar activity and the nesting observed on other low-mass stars, a link that will be further explored with ESA’s PLATO mission.

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