With the Very Large Telescope (VLT) in Chile, astronomers have found an exoplanet in a star system that is hotter and more massive than any other planet in which we know planets. The double star b Centauri (not to be confused with the triple star β Centauri) has six to ten times the mass of the sun, the main star is three times as hot and emits large amounts of ultraviolet and X-rays. In view of the exoplanets found so far, such an environment was considered possibly too unfavorable for the formation of planets. The team can now disagree. b Centauri b also keeps enough distance: the calculated distance is 560 astronomical units, i.e. 560 times as far as the earth is from the sun.
Completely strange environment
Artist’s impression of the giant exoplanet
(Image: ESO / L. Road)
The main star of b Centauri (AB) is a blue-white shining, so-called B star, explains Markus Janson’s team from Stockholm University. They have such a large mass and such a high temperature that they evaporate the surrounding gas faster than cooler stars. Therefore, some astronomers would have advocated the theory that no planets could form there. With the discovery of the directly depicted exoplanet around b Centauri, this has now been refuted. The entire system represents an environment “which is completely different from what we experience here on earth and in our solar system,” says co-author Gayathri Viswanath. Everything there is gigantic, the stars, the planet and the distances.
In any case, the exoplanet b Centauri (AB) b has ten times the mass of Jupiter and is therefore one of the most massive exoplanets at all. The ratio of the masses of stars and exoplanet is thus roughly the same as that of Jupiter to the sun, but the distance is disproportionately larger. It is unlikely that the exoplanet was created in this position only by the usual accumulation of matter, it may first have been thrown onto the orbit. The authors also suggest that so far possibly no exoplanets have been found in such long orbits around such massive stars, because the most productive approaches (the transit and radial velocity method) are simply not suitable for such objects. Your research was published in the journal Nature.
(mho)
