Betelgeuse is a red supergiant star located in the constellation of Orion, approximately 640 light-years from Earth. It is one of the largest and brightest stars in our galaxy, with a radius about 1,000 times that of the Sun and a luminosity several thousand times greater.
The new observations, published in the journal Nature, show the surface of Betelgeuse to be highly dynamic, with giant convective cells, similar to boiling water, causing the star's surface to pulsate and erupt. These eruptions are responsible for the star's mass loss, which occurs at a rate of approximately 3 x 10^-8 solar masses per year.
The researchers believe that the mass loss from Betelgeuse is driven by two mechanisms: radiation pressure and pulsation. Radiation pressure is the outward force exerted by intense radiation from the star's surface, while pulsation is the regular expansion and contraction of the star's outer layers.
According to the team, the combination of these two mechanisms creates shock waves that propagate through the star's atmosphere and carry mass away from the star. These shock waves are also thought to be responsible for the formation of the dust clouds surrounding Betelgeuse, which are visible in the ALMA images.
The new observations provide a better understanding of the final stages of evolution of massive stars like Betelgeuse. When these stars exhaust their nuclear fuel, they undergo a supernova explosion, releasing a huge amount of energy and material into the interstellar medium. The mass loss from Betelgeuse is thought to be part of the preparatory process for this eventual explosion.
Betelgeuse is expected to explode as a supernova within the next million years, and astronomers are eagerly awaiting this event. The new ALMA observations provide important clues about what to expect when this happens.
