Red supergiant stars 'dance' because they have too much gas

Scientists can finally explain why some massive stars seem to dance around in the sky even though they aren't actually moving.

As they near the end of their lives, the dancing stars are known as red supergiants, enormous stellar objects that have swelled up and cooled down. The diameter of these stars is up to 700 times that of the sun, which is equivalent to the surface of Mars. These giants can be difficult to locate with precision.

The location of a star can be determined by identifying its photo-center, or the point at the center of the light it emits, which usually lines up with its barycenter. Fixed positions are where photo-centers are found in most stars. In red supergiants, this point seems to move from side to side over time. That motion makes it difficult to locate the stars' barycenters, which are located in the center of the universe.

The future of the sun is related to red giant stars.

Researchers compared the dancing red supergiants to stars in the stable portions of their lives. The scientists looked at stars in the Perseus stellar cluster using data from the European Space Agency's Gaia space observatory.

The study found that the position uncertainties of red supergiants are larger than for other stars.

To get to the bottom of why these stars are wobbly, the team created intensity maps of red supergiants' surfaces.

The maps show that the surfaces of red supergiants are very dynamic and have a lot of energy in them. The photo-center is shifted if a bright structure flares up on the left side of a red supergiant.

This could be explained by the huge size of red supergiants. The outer shells of most stars are made up of thousands of adjacent convective cells that cycle hotter gas from the star's interior to its outer surface where it cools and sinks back down.

Red supergiants are so big that their gravity is less than at their core. Their convective cells take up between 20% and 30% of a red supergiant's substantial radius, or between 40% and 60% of its diameter. The study states that bigger convective cells can transport more gas to the star's surface.

The team's data shows that the size of the surface structures can affect how long they stay. The largest structures evolve on timescales of months or even years, while smaller structures evolve over the course of several weeks, according to a new study. He said that the location of the stars' photo-centers is always changing.

Astronomers believe that red supergiants play an important role in the evolution of the universe, as they spit out large amounts of gas and heavy elements that are important in the creation of new stars and exoplanets. Future studies of the stars' wobbling could help determine how vital materials are ejected from them.

The dancing pattern of red supergiants in the sky could teach us more about their boiling envelopes. We will be able to better understand the physical processes that cause the vigorous convection in these stars.

The study was published in a journal.

The original article was published on Live Science.

We encourage you to follow us on social media: