The record drop in brightness Betelgeuse explained spots in the photosphere

Astronomers have proposed a new explanation for the record fall of the Shine of the red giant Betelgeuse in late 2019 — early 2020. In their opinion, it is connected with processes in the outer layers of the star, such as the formation of large spots, or a General fall of temperature of the photosphere, and can not be explained by the influence of dust clouds. Article published in the journal The Astrophysical Journal.

Red supergiant Betelgeuse is at a distance of 600-700 light-years from Earth in the constellation of Orion. The mass ranges from 9.5 to 20 solar masses if it is placed in the center of the Solar system, the boundaries of Betelgeuse reach the orbit of Mars or even Jupiter. The age of the star is about eight million years, it is believed that in the next ten thousand years there will be a gravitational collapse of the core and Betelgeuse will explode as a supernova of type II.

In the period from November 2019-March 2020 Betelgeuse was a record deep low its luster in the entire history of photoelectron observations. Its apparent magnitude has fallen from 0.6 to 1.6. It was assumed that this demonstrates the willingness of the stars to explode, however, in April 2020, its brightness was restored. Was the hypothesis, confirmed by observations that the fading supergiant due to external causes dust clouds.

A team of astronomers led Tavishi Dharmawardena (Thavisha Dharmawardena) from the Institute of astronomy, max Planck put forward a different version. The researchers analyzed data of observations of the star obtained in the period from 2007 to 2020 with the help of a radio telescope APEX and infrared telescope JCMT. It was found that the fading of Betelgeuse was observed in the submillimeter wavelength range the luminosity of the star dropped by 20 percent.

These results, according to the authors, cannot be explained by dust, which practically does not absorb radiation in the submillimeter range. Numerical simulation show that the main contribution to the fading stars was to make the processes taking place in the photosphere, such as the formation of huge spots covering about half of the visible disk of the star, which is about 400 Kelvin cooler than the rest of the photosphere. Alternative ideas suggest a General reduction in the temperature of the photosphere of Betelgeuse is about 200 Kelvin, or reducing the radius of the star by about 10 percent.

However, as noted by astrophysicist Sergey Lamzin Sternberg astronomical Institute of in an interview with N+1, the influence of dust on the brightness of stars cannot be ruled out completely. “Fluctuations of Betelgeuse is not spherically symmetric. Because of this, there is an inhomogeneous temperature distribution on the photosphere of the star, followed by the outflow of matter from the overlying layers with different intensity. Where the stellar wind is more powerful, more dust is formed, which leads to the observed asymmetry of the dust shell of the star as a whole” , — said the Lamzin.

As soon as Betelgeuse explodes and why this happens can be found in our material “Clock is ticking”.

Alexander Voytyuk

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