Solar Mystery Solved: Magnetic Waves Heat Sun’s Corona

 A collaborative research team led by the Royal Observatory of Belgium (ROB) and KU Leuven has discovered that high-frequency magnetic waves may be a significant factor in maintaining the Sun’s atmosphere’s temperature in the millions of degrees. This revelation brings new understanding to the bewitching enigma of why the Sun’s atmosphere is hotter than its surface. 

This ‘coronal heating problem’ presents one of the most longstanding astrophysical conundrums. We’ve been educated since childhood that heat decreases as we distance ourselves from a heat source, but this logic doesn’t seem to apply to the Sun. 

The Sun’s only source of heat is its core, yet the corona, the Sun’s atmospheric outermost layer, is approximately 200 times hotter than the photosphere, the Sun’s surface. Prof. Tom Van Doorsselaere of KU Leuven states, “For eight decades, astrophysicists have been attempting to unravel this mystery, and increasingly, evidence suggests that magnetic waves could be responsible for heating the corona.”

This emerging understanding comes from observations made by the Extreme Ultraviolet Imager (EUI) telescope onboard the Solar Orbiter, a spacecraft from the European Space Agency ESA, that is presently observing the Sun from behind. The EUI telescope, managed by ROB, provides the most detailed images of the solar corona to date.

The footage uncovers rapid oscillations in the smallest magnetic structures of the solar corona, with the energy of these high-frequency waves contributing to the heating of the solar atmosphere.

Ref: Royal Observatory of Belgium