the Scientists of the Institute of astronomy of max Planck Society in Germany has revealed the mechanism of the mysterious loss of brightness of Betelgeuse. It turned out that the cause of the phenomenon is the giant spot that refutes the earlier hypothesis of the emission of dust clouds. Article researchers published in the Astrophysical journal.
Astronomers have spent 13 years of observations of the red supergiant in the submillimeter range (between infrared and microwave bands of the electromagnetic spectrum) using the telescope James Clerk Maxwell in the United States. It turned out that during the fall of the apparent brightness of 40 percent from October 2019 through April 2020, the star has also reduced its brightness at submillimeter wavelengths by 20 percent. Scientists have considered the radiation transfer model and showed that the probable cause was the change in temperature in the photosphere, ie the surface of the star has a giant cold spots.
Previously it was thought that the cause of the change of brightness was dust emissions. This phenomenon is typical for giant stars located at the last stage of its life cycle. They swell and the outer layers become unstable and begin to pulsate. Since the gravitational attraction on the surface of the burgeoning star is waning, pulsations can easily push the gas, which is cooled condenseries and turns to dust. Although this dust obscures visible light from stars in the submillimeter range it should emit radiation.
However, the dimming at all studied wavelengths may indicate either a decrease in the average surface temperature of Betelgeuse at 200 degrees Celsius, or on the occurrence of relatively cold areas, occupying 50-70 percent of the surface of the star. However, it is unknown whether there are giant stars mechanisms similar to those that underlie the 11-year solar cycle, during which the number of sunspots then increases, indicating the maximum activity of the Sun, then decreases.