Ross 128 b: Astronomers Find Potentially Habitable Earth-Like Planet Right On Our Doorstep

Alexandra Lozovschi

Nearby planet Ross 128 b is all the rage among astronomers. Scientists have recently discovered it not far from our solar system, and they're already speculating there's a high probability it could sustain life. According to the European Southern Observatory (ESO), this Earth-sized exoplanet is the "closest temperate world" ever detected and has now become a primary candidate in the search for alien life.

The discovery belongs to a team of astronomers led by Xavier Bonfils, from the Institute of Planetology and Astrophysics of Grenoble and the University of Grenoble Alpes, France. The researchers stumbled upon planet Ross 128 b after more than a decade's worth of working with ESO's "unique planet-finding instrument" — the High Accuracy Radial Velocity Planet Searcher (HARPS), stationed at the La Silla Observatory in Chile.

HARPS uncovered that Ross 128 b sits right on our cosmic doorstep. Lying a mere 11 light-years away, it's the second closest exoplanet to Earth, after Proxima b. Just like Proxima b, which orbits the red dwarf Proxima Centauri (the closest star to our Sun, found only 4.25 light-years away), the newly-discovered exoplanet also revolves around a red dwarf star, called Ross 128. Yet, the two red dwarfs are nothing alike.

Its parent star received its fair share of public attention about four months ago, when a report describing "peculiar" radio signals emanating from Ross 128 sparked talk that we may not be alone in the universe. However, follow-up inquiries pointed to an Earth-orbiting satellite, and not an alien civilization, as the source of the mysterious signals.

Still, Ross 128 continues to pique astronomers' interest, and here's why. Unlike the virulent Proxima Centauri, which blasts Proxima b with harmful ultraviolet and X-ray radiation, Ross 128 is significantly less active. This adds to the conjecture that the newfound planet orbiting it might harbor life.

In a statement for, Bonfils explains that contrary to Proxima Centauri, which "is particularly active, with frequent, powerful flares that may sterilize (if not strip out) its atmosphere," Ross 128 appears to be "one of the quietest" in the bunch of red dwarf stars his team investigated.

"This is the closest Earth-mass planet potentially in the habitable zone that orbits a quiet star."

Data from the HARPS revealed Ross 128 b orbits its host star 20 times closer than the Earth orbits the Sun, and it does so every 9.9 days. However, in spite of being so close to the red dwarf, the planet receives only 1.38 times more irradiation than Earth, mainly because its parent star is so cool and faint. By comparison, Proxima b is periodically battered with 30 times more extreme ultraviolet radiation than Earth.

This suggests the newfound exoplanet could be more hospitable to life than Proxima b, the other potentially hospitable planet astronomers are looking into.

Co-author Nicola Astudillo-Defru, from the Geneva Observatory in Switzerland, also believes the newfound planet is a safer bet for finding life.

"Just because Proxima Centauri blasts its planet with strong flares and high energy radiation, yes, I think Ross 128 is much more comfortable for the development of life," Astudillo-Defru told BBC News.

Discovered just last year, Proxima b is found in the nearest solar system to our own and is located 2.6 times closer to Earth than Ross 128 b. But this may no longer be the case in the future.

ESO disclosed Ross 128 b is moving closer towards us and is expected to come nearer than Proxima b, becoming our next-door neighbor in a matter of only 79,000 years — "a blink of the eye in cosmic terms."

Since Ross 128 is both smaller and cooler than our Sun, with slightly over half its surface temperature, astronomers presume the planet they found circling it has a surface temperature similar to that of our Earth. The researchers estimate the temperature of Ross 128 b lies between -60 and 20 degrees Celsius — which could accommodate life.

This would qualify the Earth-sized exoplanet (HARPS shows its minimum mass is 1.35 times that of our planet) as a temperate one. However, scientists need to study the planet's atmosphere before they can ascertain whether Ross 128 b is equipped to sustain life.

"Depending on its composition and the reflectivity of its clouds, the exoplanet may be life friendly with liquid water as the Earth, or sterile like Venus," says Astudillo-Defru.

The next step is to scrutinize Ross 128 b with giant megascopes, such as ESO's Extremely Large Telescope (ELT). As Bonfils points out, ELT would be able to search the planet's atmosphere for oxygen, methane and other possible signs of life. To that effect, ESO has already designated the Earth-like exoplanet as "a prime target" for ELT, which is scheduled to come online in the mid-2020s.