Young Star Flares Hinder Planet Formation express
A thick stew slowly cools in a pot. Suddenly, the flame beneath it flares up, and the stew begins to boil, breaking into many small whirlpools. Much the same happens to the disk of gas and dust around a young star when it experiences a flare — a sudden influx of matter from the disk onto the star.
Astronomers have long noticed such flares in young stars, but until now they couldn't trace in detail what happens to the dust in the disk during these events. In a new study, scientists ran computer simulations of the inner part of a protoplanetary disk — a region about 10 astronomical units in radius (one astronomical unit is the distance from Earth to the Sun, roughly 150 million kilometers). They accounted for gas and dust motion, radiation transfer, and dust grain growth. It turned out that the flare front is highly unstable: it quickly breaks into many small vortices, which over time merge into one compact vortex.
But this is not the end of the story. When the flare ends, the vortices gradually decay, and the disk returns to a calm state. At a distance of about one astronomical unit from the star, a dense clump forms — something like a sandbar, where dust begins to accumulate again. It is here, after the lull, that the growth of future planets can resume. So flares don't put an end to planets; they merely delay their birth.
In the Solar System, Earth lies at a distance of about 1 astronomical unit from the Sun. Perhaps our planet was born in just such a calm 'pocket' after ancient flares from the young Sun.
In Stanisław Lem's novel 'Solaris,' the planet's ocean generates vortex structures that influence the entire ecosystem — somewhat like how vortices in a protoplanetary disk govern planet formation.