The new world has been designated as Ross 128 b and is now the second closest temperate planet after Proxima b. As if this were not enough, it is the closest planet discovered that orbits an inactive red dwarf star, which increases the chances that it is a planet that could potentially harbor life.
The finding was made possible thanks to ESO’s HARPS ( High Accuracy Radial velocity Planet Searcher) instrument, installed at the La Silla Observatory in Chile. Astronomers have discovered that this low-mass exoplanet orbits its star – a red dwarf – every 9.9 days , that is, 20 times closer to its star than the distance that the Earth orbits the Sun.
However, despite this proximity, Ross 128 b receives only 1.38 times more radiation than Earth. As a result, the equilibrium temperature of Ross 128 b is estimated to be between -60 and 20 ° C , something unheard of so far.
Scientists expect this Earth-sized world to be temperate, with a surface temperature that could also be similar to Earth’s. However, uncertainty remains as to whether the planet is inside, outside, or at the threshold of the habitable zone , where liquid water can exist on a planet’s surface.
A temperate exoplanet
“This discovery is based on more than a decade of intensive monitoring with the HARPS instrument, along with data reduction and state-of-the-art analysis techniques. Only HARPS has demonstrated such precision and, fifteen years after the start of operations, it remains the best radial velocity instrument “, explains Nicola Astudillo-Defru, co-author of the study.
Red dwarfs are the coldest and weakest stars in the universe (also the most common). These characteristics make them interesting targets for the search for exoplanets, hence they are being increasingly studied. In fact, the study leader, Xavier Bonfils from the University of Grenoble (France) dubbed the HARPS program ‘The shortcut to happiness’, since it is easier to detect the little cold brothers of the Earth around these stars. , compared to stars similar to the sun.
In the case of Ross 128, it appears to be a particularly quiet star (not like Proxima Centauri and others, which emit flares that occasionally bathe the planets that orbit them in lethal ultraviolet radiation and X-rays). Thus, the planets of the Ross 128 system could become the closest known place with the possibility of harboring life.
The planet is moving towards us
This temperate world is quite close to us, barely 11 light years away from Earth, but the truth is that it is moving towards us. Experts expect it to get closer in 79,000 years, making it the closest exoplanet to Earth, within the blink of an eye in cosmic terms.
Astronomers are currently detecting more and more temperate exoplanets, and the next stage will be to study their atmospheres, composition and chemistry in more detail.
Reference: A temperate exo-Earth around a quiet M dwarf at 3.4 parsecs. European Southern Observatory. Astronomy & Astrophysics 2017
