The Sun’s composition

The Spectral Imaging of the Coronal Environment (SPICE) instrument on the ESA/NASA Solar Orbiter spacecraft records the composition of the corona, the Sun’s outer atmosphere.

The image shows the same location taken at six different wavelengths of ultraviolet light on 31 March 2022. Each image has been colour coded because the wavelengths are invisible to the human eye. The images reveal the composition of the Sun’s atmosphere because each of these wavelengths is characteristically emitted by different species of atoms at different temperatures. Along the top row the 99 nanometres (nm) image shows nitrogen at 85 000°C; the 70 nm image shows oxygen at 100 000°C; and the 75 nm image shows sulphur at 110 000°C. Along the bottom row the 76.5 nm image shows nitrogen at 150 000°C, the 78 nm image shows both sulphur and oxygen at 160 000°C, and the 77 nm image shows neon at 630 000°C.

See this image in action with this movie.

The composition revealed by SPICE is compared to the composition of the solar wind recorded by Solar Orbiter’s Solar Wind Analyser (SWA) instrument. This allows researchers to investigate the different possible acceleration mechanisms responsible for launching the solar wind.

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