Proba-3 Mission Overview
The European Space Agency’s (ESA) Proba-3 mission comprises two spacecraft engineered to maintain a precise formation flight, thereby creating artificial solar eclipses in orbit. This mission aims to observe the inner section of the Sun’s corona, addressing a gap in consistent solar observations.
ASPIICS Instrument and Observations
The ASPIICS coronagraph, aboard Proba-3, captured images utilized to create a time-lapse showing the Sun's inner corona in faint yellow. This animation integrates data from ASPIICS with data from NASA’s Solar Dynamics Observatory’s (SDO) Atmospheric Imaging Assembly (AIA), which displays the solar disc in dark orange.
Andrei Zhukov, Principal Investigator for ASPIICS from the Royal Observatory of Belgium, stated that the corona is approximately 200 times hotter than the Sun's surface. He elaborated that solar prominences are structures of relatively cold plasma, around 10,000 degrees Celsius, observed near the Sun; these are significantly cooler than the surrounding million-degree corona. Prominences are capable of expanding and erupting from the Sun, releasing plasma.
On September 21, 2025, ASPIICS observed the Sun during an active period, recording three prominence eruptions over five hours, with images acquired every five minutes. The clear capture of multiple eruptions within a short timeframe was noted as a rare occurrence.
Coronal Light and Spectral Analysis
ASPIICS observes the solar corona using various filters, including two spectral lines corresponding to different elements present in coronal gases. The prominence eruptions in the animation were captured using a spectral line emitted by helium atoms, which presents the solar atmosphere similarly to a human eye viewing a total eclipse through a yellow ASPIICS filter. The AIA image also displays helium emission. The persistent faint yellow glow of the corona is attributed to the scattering of visible light from the Sun's surface on coronal electrons.