Neutral particles can affect the shape of the solar system’s protective bubble

Interactions with neutral hydrogen molecules, coming from the interstellar medium, may be responsible for leaving the heliosphere (the bubble that surrounds the solar system and protects it from energetic particles) similar to the shape of a croissant. The discovery was made by a team led by astrophysicist Merav Ophir, of Boston University, which sought to understand the cosmic forces responsible for determining the shape of the heliosphere.

Understanding this structure and how it works is important for scientists also to understand our region and even the emergence of life on Earth. However, since we’re inside the heliosphere, trying to figure out what it looks like isn’t an easy task — but it’s not impossible either. With data from the Voyager and New Horizons missions, scientists have discovered that it could be croissant shaped style.

However, what is behind this structure remains to be discovered. For this, the authors studied heliosphere jets, which are binary emissions emitted by the sun’s poles whose shape comes from the interaction of the solar magnetic field with the interstellar field. As a result, they are not emitted in a straight line, but curved like the ends of a croissant – these ends are also the “tails” of the solar system.

These emissions are similar to other astrophysical jets observed in space, and as with other types, the sun’s jets are also unstable; Thus, the heliosphere, “drawn” by the Sun, also looks unstable. “We’re seeing these jets model as irregular plumes, and astrophysicists have wondered for years why these shapes show instability,” Ophir explained.

Thus, the team worked with computer models that focus on neutral hydrogen atoms, that is, those without a charge. Their effects on the heliosphere are not yet known, but when researchers removed these atoms from the model, the solar jets were stable; Then the authors put it back and note the return of instability to the planes.

According to the team’s analysis, this is due to the interaction of neutral hydrogen with ionized matter in the outer region of the Sun’s atmosphere. As a result, this causes the so-called “Rayleigh-Taylor instability”, which occurs at the interface between two liquids of different densities: the lighter pushes the two heavier liquids, causing a disturbance in the tails of the heliosphere.

This explanation may have implications for understanding how galactic cosmic rays enter the Solar System, which also helps to understand the environment outside the protection of the Earth’s magnetic field. “This is a huge discovery, and really puts us on the path to discovering why our heliosphere model achieves this unique shape of the croissant, while others don’t.”

The article containing the study results was published in The Astrophysical Journal.

Source: Astrophysical Journal; via: Science alertAnd Boston University