If you had to retain that name exoplanet, it would probably be that of Proxima Centauri b or, for short, Proxima b. Detected for the first time four years ago, this world extra-solar orbit around the closest neighbor of the Sun, the star Proxima centauri, has recently been confirmed. And it is only 4.2 light-years from the Sun ! It should be said that its first detection via the radial velocity method, which consists of identifying, by the spectroscopic Doppler, the changes in the spectrum of light emitted by a star in the presence of a planet in orbit around it, had left the shadow of a doubt. The measurements carried out then flirted with the limits of the instrument used, the spectroscope HARPS, mounted on the telescope of 3.6 m of the european southern Observatory (ESO) at La Silla observatory in Chile. The new detection that comes to allow the confirmation of its existence in a study published in the journal Astronomy & Astrophysics has been realized thanks to his successor, the spectroscope Espresso, installed on the Very Large Telescope (VLT) of the ESO at the Cerro Paranal Observatory, also in Chile.

Exoterre in habitable zone

These recent measurements of exceptional precision (which is three to four times higher than the previous) also allow you to lift the veil on this exoplanet neighbor in the solar system. Of information that are worth the detour ! In fact, Proxima Centauri b has a mass very close to that of the Earth (such as Proxima b = 1.17 to land mass). Which means without any doubt that it is a terrestrial planet with a rocky surface and, as such, considered relatively conducive to the development of life. This is what is commonly known as a exoterre... but that's not all ! In fact, Proxima b-orbit in addition in what is called the habitable zone of its star around which it revolves in the 11.2 days. That is to say, the distance of the planet from Proxima of the Centaur allows a surface temperature compatible with the presence of water under liquid form. A precious key for a possible development of life on this "twin" of the Earth.

A companion capricious

of course, from there, to imagine Proxima b swarming of bacteria, and even other beings more complex, there are a hell of a step to take ! To the extent that its star is a red dwarf of the kind rough, of that which bombards their environment X-ray, not really friendly. An atmosphere of ad hoc might be the shield... But does it have only one ? The good news is that a low distance to an astronomical point of view, it is certain that the next generation of instruments will not only answer this question but also learn even more about this interesting exoplanet. It is " an ideal candidate in the search for biomarkers with next generation telescopes ", advanced Jonay González Hernández, one of the co-authors of the study. Keep in mind its name : Proxima Centauri b !