A satellite has observed a solar flare and a spiky “hedgehog” on the sun in ways that have never been done before.
In February 2020, NASA and the European Space Agency launched the Solar Orbiter, which is currently revolving around our star (SN: 2/9/20). Images from the spacecraft’s closest solar flyby to yet were made public on May 18. The orbiter’s close approach to the sun—48 million kilometers closer than Mercury is—occurred on March 26 during that flyby.
Solar physicist David Berghmans of the Royal Observatory of Belgium in Brussels said, “This is remarkable to have this type of data already.”
The studies reveal a phenomenon known as the hedgehog because of the darker, colder gas spikes that it has on top of hotter stuff. According to Berghmans, the head of the orbiter’s Extreme Ultraviolet Imager, “‘Cool’ is relative here, with relation to the 1-million-degree background [plasma].” Although they are unsure of the exact reason, experts believe that the long, thin jets of solar material known as spicules are to blame.
Four Solar Orbiter instruments discovered an X-ray flare a few days before to spotting the 25,000 km wide hedgehog and watched how it impacted adjacent space. According to Berghmans, this is what the spacecraft was designed to perform.
According to him, the spacecraft is focused on “connection science.” Over the course of many hours, the equipment aboard Solar Orbiter discovered the solar flare, the shock wave it produced, the burst of charged particles it released, and the radio signals it produced. In the past, they were discovered independently over days by various telescopes.
Scientists may more accurately forecast the discharges of those charged particles, which are particularly hazardous to astronauts, satellites, and even high-flying airplanes, by weaving the events together into “a full tale,” according to Berghmans.
Through 2026, the spacecraft will make a near approach to the sun every five to six months. The orbiter will next travel closer to the sun’s poles over the following three years, giving astronomers their first direct observations of those areas.