The mysterious halo

The Sun's fiery corona reaches temperatures above a million degrees Celsius, much hotter than the surface beneath it. This counterintuitive temperature difference has long been a topic in the scientific community.

Proba-3’s ASPIICS is tackling this mystery by studying the corona very close to the Sun’s surface. It can also see more detail, detecting fainter features than traditional coronagraphs thanks to a drastic reduction in how much ‘stray’ light reaches the detector.

Joe Zender, Proba-3 project scientist, adds: “Seeing the first data from ASPIICS is incredibly exciting. Together with the measurements made by another instrument on board, DARA, ASPIICS will contribute to unravelling long-lasting questions about our home star.”

The Digital Absolute Radiometer (DARA) will measure the total solar irradiance – exactly how much energy the Sun is putting out at any one time. A third scientific instrument on Proba-3, the 3D Energetic Electron Spectrometer (3DEES), will detect electrons in Earth’s radiation belts, measuring their direction of origin and energy levels.