Scientists have discovered that meteor-like fireballs in the Sun’s atmosphere fall like showers from shooting stars during the coronal shower phenomenon. However, solar “meteors” are rather balls of plasma that heat the gas in the atmosphere around them as they fall back to the Sun’s surface at speeds of up to 150 kilometers (93 miles), rather than debris from comets or asteroids. ) every second.

Discovering these details, led by solar physicist Patrick Antolin of the University of Northumbria in England, could help scientists learn more about the Sun’s atmosphere and why it is strangely and paradoxically so much hotter than the surface. The work available on the arXiv preprints server will be published on: Astronomy and Astrophysics and was presented this week at the annual national astronomical meeting of the Royal Astronomical Society of Great Britain.

Regardless of what it’s made of, a coronal shower is subject to the same physical laws as rain on Earth. The heated material rises from the surface and cools as it rises, causing it to fall down again. On Earth it is usually water. In the Sun, plasma follows ring-like magnetic fields that protrude from the sun’s surface.

We know very little about how the coronal shower works, but the European Space Agency’s Solar Orbiter (SolO) has given us a great close-up view. In March 2022, the probe flew within just 48 million kilometers (30 million miles) of our star in the first of these audacious maneuvers. This close encounter, called perihelion, provided astronomers with a wealth of up-close data for their research.

Here, Antolin and colleagues obtained high-resolution data on clumps of plasma up to 250 kilometers (155 miles) in size falling from the coronal shower. They also found that beneath these clusters, as they fall toward the Sun, the gas in the solar atmosphere is compressed and heated to about 1 million degrees Celsius. These hot spots last for a few minutes as the clots continue to descend.

Here on Earth, something similar happens when meteorites fall (but don’t get that hot), turning chunks of rock into fireballs that erode or explode from heat and pressure. But researchers have found that things are a little different on the Sun.

Because the Sun’s atmosphere is so thin, clumps of plasma don’t undergo the kind of erosion that meteorites do here on Earth. And the loops of the magnetic field act as a kind of tunnel through which the clots move. Therefore, the plasma spheres would likely reach the surface intact, causing a brief flash of heat and light when they landed. This too was captured by SolO.

But magnetic loops also prevent the plasma from forming a tail, as meteors do. This means that it is much more difficult to see them.

“SolO orbits close enough to the Sun to detect minor events occurring in the corona, such as the effects of rain on the corona, which allows us to obtain a valuable indirect investigation of the coronal environment, which is crucial for understanding its composition and thermodynamics.” – says Antolin. “The simple detection of the coronal shower is a big step forward for solar physics because it gives us important clues about fundamental mysteries of the Sun, such as how it warms to millions of degrees.”