A recent study revealed that Sun-like stars abruptly reduce their magnetic braking force when they reach a critical rotation threshold. This discovery significantly alters what was known about stellar rotation, magnetism, activity and evolution. The phenomenon is related to solar storms, which are the product of magnetic changes in the stars' chromosphere that cause solar winds.
Stellar dynamics have shown that magnetized winds expelled by stars gradually decrease their rotation due to conservation of angular momentum, causing low-mass stars to spin slower over time. This idea was consolidated by the work of Andrew Skumanich in 1972, who discovered that rotation and various activity indicators decrease approximately with the inverse square root of age.
Based on these observations, gyrochronology was born, a technique for estimating stellar ages by measuring their rotation. However, observations made by the Kepler space telescope revealed a significant anomaly: some old and inactive stars did not follow this expected pattern of gradual deceleration.
If the Sun were to lose its magnetic field, it would cease to produce the dynamo that generates its magnetic activity, which would have profound consequences for the solar system and Earth, although the specific details of these consequences are not fully explored in the presented article.
