A study from The University of Alabama in Huntsville (UAH) proposes that tiny, charged dust grains near the sun may be key to understanding the solar corona's extreme heat. Published in The Astrophysical Journal, the research challenges long-held assumptions about energy transfer in the sun's outer atmosphere. The corona's temperature reaches millions of degrees, while the surface below remains relatively cool at about 5,500 degrees Celsius.
The finding could fundamentally alter how scientists view the heating mechanism of the corona, a puzzle that has persisted for decades. Traditional models have focused on magnetic fields and waves, but none have fully accounted for the observed temperature disparity. The new work suggests that cosmic dust acts as a conduit or modulator for energy, potentially bridging a critical gap in existing theories.
The UAH researcher modeled how charged dust grains interact with plasma and electromagnetic fields in the corona. These grains, likely originating from comets and asteroids, become electrically charged in the sun's intense radiation environment. The study indicates they may absorb, scatter, or reradiate energy in ways that significantly raise local temperatures.
If validated by further observation or simulation, this mechanism could reshape predictive models of solar activity and space weather. It may also offer insights into stellar physics beyond our own sun. However, the hypothesis relies on assumptions about dust density and distribution that remain uncertain.
Independent astrophysicists caution that the model requires direct measurement to confirm. The Parker Solar Probe, which has sampled the corona's outer edge, could potentially test some of these predictions in future flybys.