Yesterday ESO held a press conference to announce that probably they discovered an exoplanet orbiting Proxima Centauri, the nearest star to the solar system. A team of astronomers led by Guillem Anglada-Escudé from Queen Mary University of London found what was called Proxima b, a planet a little more massive than the Earth orbiting in the habitable zone of its star.

ESO astronomers are conducting a campaign for the search of exoplanets around nearby stars called Pale Red Dot. The name is inspired to the expression Pale Blue Dot used by the astronomer Carl Sagan to indicate the Earth photographed by NASA’s Voyager 1 space probe when it was about six billion kilometers from Earth.

The Pale Red Dot campaign uses the HARPS spectrograph and during the first half of 2016 Proxima Centauri has been observed regularly. At the same time, the star was monitored by other telescopes around the world. The planet Proxima b’s traces were detected using the radial velocity method, based on perturbations on the star’s speed caused by the gravitational effects in place between it and the planet.

The analysis of those perturbations indicated the presence of a planet with a mass at least 30% greater than the Earth’s orbiting at a distance of about 7 million kilometers (a little more than 4.3 million miles) from Proxima Centauri. That distance is only 5% of that of the Earth from the Sun but the star is a red dwarf star that emits a much dimmer light than the Sun. The consequence is that Proxima b is within its star’s habitable zone, the one in which water can be liquid on the planet’s surface if its atmosphere has characteristics similar to those of Earth’s atmosphere.

We know nothing of Proxima b’s atmosphere, we’re not even certain that the planet has an atmosphere at all. At the moment we’re not even certain that it’s a rocky planet even if the data indicates that this is its most likely nature. Additional reasons for caution arrive from Proxima Centauri’s characteristics, not really ideal for the development of life forms.

Proxima Centauri’s main problem is that despite its small size is very active because the phenomenon of convection within it generates a magnetic field with an occasional flare that can be very violent. The consequence is that Proxima b is hit by strong ultraviolet and even X-ray emissions with an intensity that was estimated to be 400 times greater than those that hits the Earth.

Those conditions don’t give a certainty that there can’t be life on Proxima b but they should be adapted to that kind of stellar flares. The planet could always show the same face to Proxima Centauri just like the Moon to the Earth because of its proximity and in that case there are areas not directly affected by the eruptions where conditions could be more favorable for life forms.

The research that led to the discovery of Proxima b was described in an article just published in the journal “Nature”. However, this is only the beginning of this exoplanet’s studies. First of all, we need confirmation of its existence because in October 2012 ESO astronomers announced the discovery of a planet around Alpha Centauri B that raised a lot of skepticism and probably doesn’t really exist. In these four years there were many advances in the study of exoplanets but we need more data on Proxima b.

The existence of a potentially habitable exoplanet that orbits the closest star to the Sun is certainly a great incentive for astronomers to study it with other telescopes. Some types of studies require a passage of the planet in front of its star but from this point of view Proxima b’s location isn’t good so at least in the near future that won’t be possible.

Right now, there’s a very interesting discovery because Proxima b is the closest exoplanet we could find and has characteristics that raised even too much enthusiasm. Definitions such as “Earth’s twin” are definitely far-fetched but we’ll certainly hear more about this planet.