The new ultra-high resolution images of the Sun
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ESA & NASA / Solar Orbiter / EUI Team
The Solar Orbiter mission, the result of a collaboration between ESA and NASA, left for our star in February 2020 with the aim of providing an unprecedented vision of the aspect of the Sun and to investigate in detail how it works. On board the probe there are ten different instruments: some of them are remote sensing, in order to observe, at high resolution, the phenomena in the lower layers of the solar atmosphere, others are in situ detection instruments that monitor the conditions around the Orbiter. Among the remote sensing tools there is also the Italian coronographer Metis, which is able to observe the solar corona (the outermost layer of our star) in the visible band and in the ultraviolet band.
In particular, the scientific target of the mission is the heliosphere, the region of space around the Sun, which extends beyond the planets of the Solar System and which is affected by solar activity itself. Inside the heliosphere, in fact, there are electrically charged particles, most of which have been ejected from the star to form the solar wind, which carries with it the surface magnetic field of the Sun. The solar wind and its magnetism associated are responsible for space weather phenomena, such as solar storms, which can threaten technologies on Earth.
Therefore, to study the effects on the heliosphere, the results of the in situ instruments, which record the particles and magnetic fields that cross the probe, must be traced back to the events recorded on the visible surface of the Sun by the remote sensing instruments . There are particular situations in which making these results collimate is easier, i.e. when the spacecraft is very close to the Sun: in this case, the closer it is to our star, the greater the detail that the remote sensing instruments can observe and at the same time it is easier for in situ instruments to trace the activity of electric particles, from the Orbiter to the Sun.
The first perihelion of the probe On March 26, Solar Orbiter found itself in its first perihelion , that is the point of the orbit closest to the Sun, which corresponds to about one third of the distance between the star and our planet, inside the orbit of Mercury. The close pass occurred at a time of fairly intense solar activity: the spacecraft absorbed several solar flares and a mass ejection from the corona, which later triggered geomagnetic storms and radio blackouts on Earth. Among the phenomena captured by remote sensing instruments, one of the most curious is a geyser of hot and cold gas, which extends for more than 25,000 kilometers in all directions and which has been nicknamed “solar hedgehog”. In addition, the instruments made it possible to capture images of the solar South Pole in high resolution. These are of particular interest to scientists who study the behavior of the Sun and its cycles of activity, which last 11 years and which occur with the periodic generation of sunspots, flares and plasma eruptions. A period of intense investigation opens up for those working on the Solar Orbiter.
"The images are truly breathtaking," says David Berghmans, principal investigator of the instrument that captures high-resolution images of the solar corona. "Even if Solar Orbiter stopped acquiring data tomorrow, I would be busy for years trying to understand all these things."
The "solar hedgehog" captured by the Solar Orbiter. Credit: ESA
The highest resolution image of the solar South Pole. Credit: ESA
The future of Solar Orbiter Researchers' efforts are now directed towards investigating the connection between what the images portray and the probe's in situ detections: in other words, how the phenomena that occurring in the lower atmosphere of the Sun can affect solar weather events. Analyzing this data in the future could lead to real-time space weather forecasts, shielding technologies on Earth and in space from the threat of solar storms. Furthermore, Solar Orbiter continues its mission: the spacecraft is already on its way to its next perihelion, which will take place on October 13, 2022. On December 24, 2026, then, the spacecraft will encounter Venus for the fifth time, tilting its orbit of 24 degrees and allowing you to observe the polar regions of the sun as directly as possible.
"We are so excited about the data quality of our first perihelion," says Daniel Müller, ESA project scientist for Solar Orbiter. “It's almost hard to believe that this is just the beginning of the mission. We will be very busy ".
