Grenoble (France): Astronomers have discovered a potentially life-friendly exoplanet in our immediate cosmic neighborhood. The earth-sized celestial body Ross 128 b orbits a red dwarf star just about eleven light years away - probably in the habitable zone. This makes him the second closest known planet after Proxima Centauri b with a temperate climate, as the researchers in the journal "Astronomy & Astrophysics" report.
The exoplanet Ross 128 b orbits an amazingly quiet red dwarf - and could be life-friendly. © ESO / M. Kornmesser
For a long time, our immediate cosmic neighborhood has left planetary hunters out: exoplanets were discovered, especially at greater distances. But meanwhile the picture has changed. In the meantime, astronomers have tracked down seven earth twins around the 40 light-years distant star TRAPPIST-1, as well as an only 14 light-years distant super-earth and even one earth-twin around our neighboring star Proxima Centauri: At just four light-years away, Proxima Centauri b is the closest earth-like planet known to us.
Now astronomers around Xavier Bonfils of the Institut de Planétologie et d'Astrophysique at Grenoble have tracked down an earth-like exoplanet that is almost as close to us. In search of earth twins, the team had targeted the red dwarf star Ross 128, about eleven light-years away, with the HARPS instrument of the European Southern Observatory (ESO) at La Silla Observatory in Chile - and made a find.
The newly discovered exoplanet Ross 128 b orbits its parent star once in 9.9 days, as the scientists report. However, it pulls its tracks twenty times closer to the star as the earth orbits the sun. Nevertheless, there is only 1.38 times as much radiation on the planet as on Earth. Because the red dwarf is only about half as hot as our sun.
The interstellar neighborhood of the Sun, including Ross 128. Copyright: Public domain
The temperature on Ross 128 b must therefore be between minus 60 and plus 20 degrees Celsius. It is considered by the astronomers as a moderate planet. However, whether it actually lies in the habitable zone where liquid water can exist on the surface of a planet has not yet been conclusively clarified.
But at least the chances of life on Ross 128 b seem to be better than on the earth twin of our next neighbor. Because many red dwarfs are so active that they repeatedly bombard their planets with dangerous ultraviolet and X-rays. This is also the case with Proxima Cenaturi. However, Ross 128 does not seem to possess these problematic features for life development, as the team reports:
It is a particularly quiet star.
For this reason, the "gentle" Red Dwarf is now increasingly in focus regarding search for life in space. It is interesting for yet another reason: As the researchers report, the system is moving towards us and will probably be our closest neighbor star system in just 79,000 years - which is a blink of an eye on cosmic timescales. Ross 128 b will then replace Proxima b as the nearest exoplanet.
Source: Astronomy & Astrophysics manuscript no. Ross128˙final˙v3
