Newly discovered Earth-sized planet looks to be life-friendly

Nov. 15 (UPI) -- Scientist have discovered a nearby Earth-like exoplanet with conditions favorable to life.

The planet orbits Ross 128, an inactive red dwarf star. The small, dim and quiet sun translates to moderate temperatures on Ross 128b. Scientists suspect the temperate planet may offer them their best chance yet at finding alien life.

"This is the closest Earth-mass planet potentially in the habitable zone that orbits a quiet star," Xavier Bonfils, an astrophysicist at the University of Grenoble Alpes in France, told Space.com.

Ross 128 and Ross 128b lie just 11 light-years from Earth, making the exoplanet the second closest temperate planet after Proxima b.

Ross 128b's transit was first revealed among the data gathered by the European Southern Observatory's HARPS instrument, located at the La Silla Observatory in Chile.

"This discovery is based on more than a decade of HARPS intensive monitoring together with state-of-the-art data reduction and analysis techniques," Nicola Astudillo-Defru, astronomer at the University of Geneva in Switzerland, said in a news release. "Only HARPS has demonstrated such a precision and it remains the best planet hunter of its kind, 15 years after it began operations."

Often, red dwarfs release periodic flares. The blasts of ultraviolet and X-ray radiation can rip away a nearby exoplanet's atmosphere and limit the possibility for alien life. But Ross 128 is rather quiet, suggesting conditions on Ross 128b are potentially peaceful enough for life to emerge.

Ross 128b orbits its host star once every 9.9 days and is 20 times closer to its host star than Earth is to the sun. Despite its close proximity, the alien world receives only 1.38 times more irradiation. Ross 128 emits just half the energy of the sun.

As of now, scientists aren't sure whether the alien world is in or out of the habitable zone -- the orbital range in which exoplanets can host water in liquid form. They hope to find out during follow up analysis using ESO's Extremely Large Telescope. Scientists also hope to learn more about the exoplanet's atmosphere.

"New facilities at ESO will first play a critical role in building the census of Earth-mass planets amenable to characterization," researcher Xavier Bonfils said. "In particular, NIRPS, the infrared arm of HARPS, will boost our efficiency in observing red dwarfs, which emit most of their radiation in the infrared. And then, the ELT will provide the opportunity to observe and characterize a large fraction of these planets."

Scientists described their discovery of Ross 128b in the journal Astronomy & Astrophysics.