Rocky exoplanet discovered near Earth's neighboring star

Barnard's Star is a famous star located “only” six light years away. It was discovered at the beginning of the last century by the astronomer Barnard, hence its name. It's a type star red dwarfthat is to say a very small sun barely larger than the planet Jupiter and half as hot as ours. Red dwarfs are the smallest category of stars capable of thermonuclear fusion, but their light is different from that of the Sun — they emit mainly red light — and their life expectancy is in the tens or even trillions of billions of years. years.

It was thanks to ESO's Chilean Very Large Telescope (and its ESPRESSO instrument) that the team was able to announce this resounding discovery. Be careful, this planet is not a future tourist destination, nor probably a place where life could have developed. It is approximately half as massive as Venus, but above all much too close to its star, which it circles in just 3.15 Earth days. Its surface temperature would be around 125°C; if water existed there, it has probably since evaporated.

Barnard's star is also known for its stellar eruptions, spotted in particular in 1998 and 2019, and this new exoplanet is 20 times closer to its star than Mercury is to the Sun! If it had an atmosphere, then the polar auroras were certainly incredible (and dangerous) during these events…

The fact remains that this discovery is famous in more than one way, notably because of the very low mass of the exoplanet and its “proximity”; it is also one of the smallest rocks ever discovered outside the Solar System.

Marginal, but fun to know… Normally, when an exoplanet is first discovered around a star, it takes the name of the star to which we add “b”, like Proxima b. But here, we are in a special case: in 2018, a Super-Earth type exoplanet was announced and therefore took the name Barnard b, unfortunately contested since. This new rocky planet will probably have another name to avoid giving birth to two “babies”…