Space

Barnard b: new planet discovered 6 light years from us. Here's what we know

Barnard b is a rocky near-Earth planet that makes a full circle around its star in just 3.15 Earth days. Its ground temperature is 125 degrees centigrade.

2 October 2024

3' min read

There is, there is not, yes come on we are finally sure: there is! It is the story of the small, rocky planet circling the Barnard star, the second closest to Earth, only six light years away.

Considering that the farthest galaxies we measure are 13 billion light years away and beyond, the new planet is practically on our doorstep.

Discovered with the European VLT telescopes in Chile, among the largest and most perfected in existence, the scientific work that has just appeared puts an end to a misunderstanding that has lasted since 2018, when there was an initial announcement of the discovery of a planet around this star, but subsequent observations denied the discovery.

It was a mistake, even in science they make mistakes, but in general they do not escape subsequent testing.

This time, the large group of researchers, including several Italians from the National Institute of Astrophysics, Inaf of Turin, Trieste and Palermo, is very sure and has subjected the results of the five years spent studying the Barnard star to all the necessary verifications. Indeed, there is reason to believe that traces of three other planets appear in the measurements, but this will be confirmed by future research.

Barnard b, as it is called from now on, is a rocky planet, its mass is a third of that of the Earth, and it makes a full circle around its star in just 3.15 Earth days, so its year is not even half as long as one of our weeks.

It is very close to its star, twenty times closer than Mercury is to the Sun, so its ground temperature is very high, we are talking 125 degrees Celsius, even though the parent star is relatively cold.

With these characteristics, it is "one of the lowest-mass exoplanets known and one of the few with a mass less than that of the Earth," explains González Hernández, head of the team of scientists who discovered it. "Even though the star is about 2,500 degrees cooler than our Sun, it is too hot to keep liquid water on the surface."

The Barnard star has an important peculiarity, measured in 1926 by the astronomer Edward E. Barnard himself: it is the fastest star in the sky 10".3 arc, in other words, in three years it moves across the sky as much as the diameter of the Moon appears to us.

It is an enormity, the other stars visible to the eye move, always of apparent motion let's be clear, so little in a hundred years that we have been calling them fixed stars since the time of Archimedes.
Although it is very close, and therefore apparently easier to study, Barnard's star has always given astronomers a hard time, due to its apparent speed in the sky and the supposed presence of planets around it.

The first announcement dates back to 1963: Peter van de Kamp claimed to have discovered, while studying the star for twenty years, a companion, never confirmed, with an enormous mass, one and a half times that of Jupiter.
The first extrasolar planet was discovered in 1995, with a relatively small telescope but a brilliant insight into the method to be used, by Robert Mayor, Nobel Prize winner for physics in 2019, together with his PhD student Didier Queloz.

Today we know thousands but there are probably billions and billions in the Universe, the hunt has just begun and Italy is doing well with its national Galileo telescope in the Canary Islands, TNG, and space observatories, such as the exceptionally innovative European PLATO, designed in Italy.