We now have the highest resolution image of the Sun’s entire disk and outer atmosphere , aka the corona, that we’ve ever seen: an 83 million-pixel snapshot that shows the Sun in unprecedented detail.
It was the Solar Orbiter spacecraft that captured the most detailed image ever seen of the sun’s explosive lower atmosphere, revealing dynamic and volatile eruptions. This joint project between NASA and the European Space Agency (ESA), was approximately 75 million kilometers away when it took the images. Halfway between our planet and the Sun.
The image is the result of a mosaic of 25 individual images taken by the Solar Orbiter spacecraft’s Extreme Ultraviolet Imager (EUI) instrument on March 7 , as it crossed between Earth and the Sun. And a team from University College London used the data sent back by the orbiter to create the highest resolution image yet.
Taken one after another, the entire image was captured over a period of more than four hours because each mosaic takes about 10 minutes, including the time it takes for the spacecraft to point from one segment to the next, and its resolution, 83 million pixels. on a 9148 x 9112 pixel grid , it’s ten times better than what a 4K TV screen can display.
Solar Orbiter captures images of the Sun at a wavelength of 17 nanometers, in the extreme ultraviolet region of the electromagnetic spectrum . This reveals the Sun’s upper atmosphere, the corona, which has a temperature of around a million degrees Celsius.
At the same time as the EUI observations, the SPICE instrument was examining the different elemental components of the solar atmosphere, from the chromosphere to the corona. These different layers have different temperatures, and the ultraviolet light comes from different excited atoms.
In these images, purple represents hydrogen gas at 10,000°C, blue represents carbon at 32,000°C, green represents oxygen at 320,000°C, and yellow represents neon at 630,000°C. This type of information will help scientists understand how the temperature rises through the Sun’s atmospheric layers, which, contrary to what we would imagine, is much higher in the corona than at the surface (around 5,000 °C).
Here you can zoom in on the ESA/NASA image.
If you look closely, at the 2 and 8 o’clock positions on the edges of the Sun, you can see dark filaments projecting from the surface. These ‘bulges’ are prone to eruption, spewing huge amounts of coronal gas into space and creating ‘space weather’ storms.
Having more and more data about our star will allow solar physicists to trace the powerful eruptions taking place in the corona through the lower atmospheric layers. It will also allow them to study how temperature rises through rising atmospheric layers.
And this is just the beginning. In the coming years, the spacecraft, which was launched in February 2020, will repeatedly fly so close to the Sun. Future perihelions will see Solar Orbiter plunge even a little closer, up to 42 million kilometers from the Sun’s surface.
Its ten instruments will capture new detailed images of the sun’s atmosphere, measure its magnetic field and the solar wind emitted by the star as it hits the spacecraft.
Reference: ESA & NASA/Solar Orbiter/EUI team; Data processing: E. Kraaikamp (ROB)