A new time-lapse reveals the Sun’s inner corona glowing a faint yellow, offering a rare look at the hottest layer of our star’s atmosphere. The footage was created using images from the ASPIICS coronagraph aboard Proba-3, capturing a region of the Sun that is normally hidden from view.
How Proba-3 Creates Solar Eclipses in Space
Proba-3 is a European Space Agency mission made up of two spacecraft that fly in extremely precise formation. By aligning perfectly in orbit, the pair can block the Sun’s bright surface and create artificial solar eclipses, allowing scientists to observe the Sun’s inner corona directly.
The animation combines observations from two space instruments. Proba-3’s ASPIICS coronagraph shows the inner solar corona in yellow, while NASA’s Solar Dynamics Observatory provides images of the solar disc in dark orange using its Atmospheric Imaging Assembly (AIA).
Extreme Heat and Cooler Structures Near the Sun
“The corona is extremely hot, about two hundred times hotter than the Sun’s surface,” explains Andrei Zhukov from the Royal Observatory of Belgium, Principal Investigator for ASPIICS.
“Sometimes, structures made of relatively cold plasma (charged gas) are observed near the Sun – although these are still around 10,000 degrees Celsius, they are much colder than the surrounding million-degree hot corona – creating what we call ‘a prominence’.”
These prominences are made of dense plasma suspended above the Sun’s surface. Over time, they can stretch outward, break apart, and erupt, sending solar material flying into space in multiple directions.
A Rare Burst of Solar Activity Captured
The time-lapse was recorded during a particularly active phase on 21 September 2025. ASPIICS captured one image every five minutes, documenting three separate prominence eruptions within just five hours.
“Seeing so many prominence eruptions in such a short timeframe is rare, so I’m very happy we managed to capture them so clearly during our observation window,” adds Andrei.
Seeing the Sun Through Different Filters
ASPIICS studies the solar corona using several filters, including two distinct ‘spectral lines’. Each spectral line corresponds to a specific chemical element present in the Sun’s atmosphere.
The prominence eruptions in this animation were recorded using a spectral line emitted by helium atoms. This allows the solar atmosphere to appear much like it would to the human eye during a total solar eclipse when viewed through a yellow ASPIICS filter. The AIA image also shows helium emission, but in a different spectral line.
Why the Corona Glows Yellow
The faint yellow background glow seen in the corona comes from visible sunlight scattering off electrons in the Sun’s outer atmosphere. This subtle light reveals the structure of the corona even when no eruptions are taking place.
Completing a Missing Piece of Solar Observation
Advanced onboard positioning systems allow the two Proba-3 spacecraft to maintain their precise alignment and repeatedly generate eclipses in orbit. This capability lets scientists observe the innermost portion of the Sun’s corona consistently for the first time, filling a long-standing gap in solar research and offering new insight into how our star behaves.
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