31 agosto 2016
It has mass similar to that of Earth. And its temperature means that, at least theoretically, it could host water in a liquid state. The sketch of the rocky planet discovered around the closest star to the Sun
Of all the exoplanets discovered so far, here is one that is truly noteworthy. And not just because its mass is extremely similar to Earth's (1.3 times that of our planet, to be precise), or because its temperature makes it a potential candidate for hosting water in a liquid state on the surface. The big news is that it is extremely close: Proxima b, this is the name of the rocky planet, in fact orbits Proxima Centauri, the closest star to our Sun, about four light-years from the Solar System. Giving the news, in the pages of Nature, was the team of Guillem Anglada-Escudé, who put together measurements collected by two telescopes of the European Southern Observatory (Eso) between 2000 and 2014 and other observations collected in January-March 2016.
The scientists, in particular, analyzed so-called Doppler measurements, which are useful for calculating small displacements of a star due to the gravitational force of any planets orbiting it. According to the researchers' observations, a hot planet of Earth-like mass would be found near Proxima Centauri, whose orbital period would be just over 11 days. The planet, to be precise, would be about 7.5 million kilometers away from the star-just for comparison, let us recall that the Earth is about 150 million kilometers from the Sun . The orbital period, scientists still say, means that Proxima b is in the so-called temperate zone, which means that the planet could, at least theoretically, harbor liquid water on its surface.
In fact, we still know too little about it: the potential habitability of the rocky planet is a matter of debate, and further observations of its atmosphere will be needed to dispel reservations about it. There is also the fact that its proximity to the star means that the planet is most likely to be targeted by much stronger X-ray fluxes than those reaching Earth from the Sun. At present, it is not known whether Proxima b has a magnetic field capable of shielding it from such radiation, as is the case with our planet. “In the next few centuries, certainly humankind may try to explore the planet with robots,” Artie Hazas explains in a piece accompanying the scientific article. “Proxima Centauri will live hundreds or thousands of times longer than our Sun. So, any life forms on the planet [or our own, should we decide to move up there, nda], could evolve long after the Sun is extinguished
