They capture, for the first time, the south pole of the Sun

BarcelonaThe European Space Agency's (ESA) Solar Orbiter spacecraft has captured images of the Sun's south pole for the first time in history. This milestone represents a major advance in our understanding of the Sun's magnetic field, the Sun's cycle, and space weather. Until now, all our images of our star were from the Sun's equator, as Earth, the other planets in its orbit, and all spacecraft orbit the star in a disk called the ecliptic plane.

Solar Orbiter, however, has managed to break away from this plane thanks to a new orbit inclined at an angle of 17 degrees below the Sun's equator. This has allowed the mission to observe the Sun from a completely new position. Now the spacecraft will continue its passage through this new inclination. "The views from our Solar Orbiter mission are the beginning of a new era of solar science," said Carole Mundell, ESA's Chief Scientist.

The Solar Orbiter images were captured by three science instruments: the Polarimetric and Helioseismic Imager (PHI), which images the Sun in visible light and maps its magnetic field; the Extreme Ultraviolet Imager (EUI), which captures images in ultraviolet light, revealing the million-degree gas in the Sun's corona; and the Spectral Imaging of the Coronal Environment (SPICE) instrument, which captures light from different temperatures of gas on the Sun's surface, revealing the Sun's different layers.

"We didn't know exactly what to expect from these first observations, as the Sun's poles are literally terra incognita," explained Sami Solanki, who leads the PHI instrument team at the Max Planck Institute for Solar System Research in Germany. As well as being the first spacecraft to capture images from this perspective, Solar Orbiter is also the closest it has ever come to the Sun.

The mission's discoveries

And what have been the mission's findings? For now, Solar Orbiter has already discovered that currently, at the south pole, the Sun's magnetic field is in a chaotic state, which would indicate that the magnetism between the north and south poles is not well-defined. However, this is nothing abnormal and is part of the Sun's cycle: we would now be in the period of solar maximum, the moment of maximum activity of the star, which occurs every 11 years. In the next 5 or 6 years, the Sun will reach its next solar minimum, a time when its magnetic field will be more orderly. "Exactly how this accumulation occurs is not yet fully understood, but Solar Orbiter has arrived at high latitudes at just the right time to follow the process from a unique and advantageous vantage point," explains Solanski.

Another discovery has been achieved thanks to SPICE. The instrument has managed to use precise tracking of spectral lines to measure the speed at which clumps of solar material move. These measurements could reveal how particles are ejected from the Sun and therefore could explain how the star produces the solar wind, one of the main objectives of the Solar Orbiter mission. "This is just the first step in thestairway to Heaven from Solar Orbiter: In the coming years, the spacecraft will move further away from the ecliptic plane to obtain ever-better views of the Sun's polar regions. This data will transform our understanding of the Sun's magnetic field, the solar wind, and solar activity," said Daniel Müller, project scientist.