Betelgeuse is the closest red supergiant star to our planet, and one day it will explode as a supernova. In recent days it has increased its brightness, could its end be near?

At the end of 2019 Betelgeuse got everyone excited when it started to darken noticeably. A few days ago it did the opposite, increasing its normal brightness by 156%, causing surprise and uncertainty among the astronomical community. The star Betelgeuse is a bright, flickering red dot on the right shoulder of the constellation Orion. Astronomers adopt it as a giant with regular changes in brightness every 400 days.

This star is classified as a supergiant due to its diameter, which is about 384 million kilometers or 2.58 astronomical units. If it were located in the center of our solar system, it would be the size of the orbit of Jupiter. What is an astronomical unit? It is a unit of length equal, by definition, to 149,597,870,700 meters, which is roughly equivalent to the average distance between the Earth and the Sun.

The fate of this type of star is to explode as a supernova. When that happens, it will be visible even in the day. But before that happens, their activity has aroused great interest among the astronomical community.

Astronomers have deduced that the star ripped away a large part of its visible surface in 2019. Something never seen before in a star. gloss variability The first clue came when the star mysteriously dimmed in late 2019. A huge cloud of dark dust formed from the ejected surface as it cooled. Currently the star’s photosphere continues to slowly recover. However, the interior resounds like a bell struck with a sledgehammer, disrupting the normal cycle of the star.

This does not mean that the gigantic star will explode soon, but the convulsions of the last stage of its life do not cease to amaze scientists and astronomers. A few days ago its brightness increased by 56% of normal.

Darkening in 2019

By analyzing data from NASA’s Hubble Space Telescope and other observatories, it has been concluded that the star literally exploded in 2019, losing a substantial part of its visible surface and producing a gigantic surface mass ejection (SME). Something never seen before in the behavior of a common star.

Our Sun ejects parts of its tenuous outer atmosphere, the corona, in an event known as a coronal mass ejection (CME). But the Betelgeuse ejecta took off 400 billion times more mass than normal. Astronomer Miguel Montargès and his colleagues from the Paris Observatory and KU Leuven investigated the event through the VLT of the European Southern Observatory. At that moment they contemplated something totally unusual in the history of astronomy: in just a few weeks the star had returned to its normal brightness, in April 2020.

These new observations shed clues about how red stars lose mass at the end of their lives as their nuclear fusion furnaces burn out, before exploding as supernovae. The amount of mass loss significantly affects your fate. However, Betelgeuse’s weird behavior is not evidence that the star is about to explode. So it’s not a sign of an impending explosion.

They are now putting together all the pieces of the puzzle of the star’s behavior before, after, and during the eruption, including new data from NASA’s Hubble Space Telescope and the American Association of Variable Star Observers (AAVSO).

The outburst in 2019 was caused by a plume of convection bubbling up from inside the star. It produced shocks and pulsations that blew away part of the photosphere, leaving the star with a large cold surface beneath the cooling dust cloud. A piece of photosphere was shot into space and cooled to form a cloud of dust that blocked out the light from the star seen by observers on Earth.

The dimming, which began at the end of 2019 and lasted for several months, was very noticeable, even to observers who monitored the change in brightness of the star.

Pulsations

Even more fantastic, the 400-day pulsation frequency of the supergiant no longer exists. For almost 200 years, astronomers have measured this rate of change in brightness variations and the motions of Betelgeuse’s surface. His interruption attests to the intensity of the explosion.