Superflare of a nearby star seen in detail

Impression of an eruption at V1355 Orionis. His partner in the background. 1 credit

A team of Japanese astronomers has successfully observed a superflare of a star near the sun through observations made with a combination of telescopes both on Earth and in space. The sun can have outbursts in the form of solar flares, prominences, or coronal mass ejaculations (CMEs), but outbursts from some stars can be up to ten times more powerful than the largest outburst ever seen on Earth. the sun. V1355 Orionis is one such star, 400 light years away and forming a binary star with another companion. With the 3.8 m Seimei telescope in Japan and the Transiting exoplanet study satellite (TESS) from NASA in space, they monitored V1355 Orionis. It was already known that the star has an erratic character and sometimes has huge explosions and indeed one could be completely monitored, an explosion that released 7 x 10^35 a lot of energy. Turns out it started with a prominence jutting out of the star’s surface, a long, jagged bridge of matter in the star’s atmosphere. The speed of matter in the prominence was at least the escape velocity of the star (347 km/s, possibly as high as 1690 km/s), which means the gas was able to escape the star’s gravity and that it could grow into a CME. , a wave of hot plasma projected into space. Billions of tons of matter were released into space (9.5 × 10^18g m < 1.4 × 10^21g).

More information can be found in the journal of Shun Inoue et al, Detection of a high-velocity prominence flare leading to a CME associated with a superflare on the RS type star CVn V1355 Orionis, The Astrophysical Journal (2023).

Source: NAOJ.

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