The orbit of Ross 128 b is 20 times more proximal (20 times closer) than the distance between the Earth and the Sun - but the planet receives only 1.38 times more irradiation, which keeps its equilibrium temperature between -60°C and 20°C (-76°F and 68°F).
Astronomers' instruments are not yet sensitive enough to spot Earth-size planets in Earth-like orbits around stars similar to our sun.
"Twenty years ago, no one would have believed that red dwarf stars - the runts of the cosmos - were good candidates for biology", Dr. Seth Shostak, senior astronomer at the SETI Institute in Mountain View, California, told NBC News MACH in an email.
The planet is orbiting a red dwarf star that's judged to be much more stable than Proxima Centauri, which is known to throw out flares of deadly ultraviolent and X-ray radiation. Those wobbles shift stars' spectrums, and by tracking these shifts, HARPS can infer planets are present.
Such megascopes should be able to resolve Ross 128b and even search its atmosphere for oxygen, methane, and other possible signs of life, Bonfils said.More news: Mariah Carey's security guard threatens to sue for sexual harassment
Although it is now 11 light-years from Earth, he said Ross 128 is moving towards us and is expected to become our nearest stellar neighbour in "just" 79,000 years - a blink of the eye in cosmic terms. However, in "only" 79, 000 years, this will all change as Ross 128 is moving towards us. After taking 116 measurements with HARPS, the team was able to conclude that an Earth-sized planet was orbiting around the star. However, Ross 128 b is the "quietest" nearby star to host a temperate exoplanet. It's also considerably more hospitable than our nearest Earth-like neighbour, Proxima Centauri b.
According to the research, the new planet completes an orbit around Ross 128 in just under 10 days. But it is close enough to Ross 128 that it absorbs warmth sufficient for liquid water, one of the requisite ingredients for life, to potentially exist on the surface. So unfortunately, it would be a stretch to label Ross 128 b as "potentially habitable".
Alongside the ESA, NASA's Kepler space telescope has also been hunting for exoplanets and since 2009 has found some 30 planets that fall within their host star's habitable zone.
The magnitude of the wobbles indicates that the planet is at least 1.35 times the mass of Earth but could easily be twice the mass of Earth. If we have, it'll not only offer the potential to see what another planet like our own looks like - but potentially to meet the aliens that live there, or to move there ourselves.
While researchers have expressed excitement over the discovery, the ESO notes: "Uncertainty remains as to whether the planet lies inside, outside, or on the cusp of the habitable zone, where liquid water may exist on a planet's surface".
When Méndez's team looked at the results, they saw something peculiar: some odd, semi-repeating signals coming from Ross 128.