Astronomers Find An Earth-Size World Just 11 Light Years Away (arstechnica.com)

Astronomers have discovered a planet 35 percent more massive than Earth in orbit around a red dwarf star just 11 light years from the Sun. "The planet, Ross 128 b, likely exists at the edge of the small, relatively faint star's habitable zone even though it is 20 times closer to its star than the Earth is to the Sun," reports Ars Technica. "The study in the journal Astronomy & Astrophysics finds the best estimate for its surface temperature is between -60 degrees Celsius and 20 degrees Celsius." From the report: This is not the closest Earth-size world that could potentially harbor liquid water on its surface -- that title is held by Proxima Centauri b, which is less than 4.3 light years away from Earth and located in the star system closest to the Sun. Even so, due to a variety of factors, Ross 128 b is tied for fourth on a list of potentially most habitable exoplanets, with an Earth Similarity Index value of 0.86. In the new research, astronomers discuss another reason to believe that life might be more likely to exist on Ross 128 b. That's because its parent star, Ross 128, is a relatively quiet red dwarf star, producing fewer stellar flares than most other, similar-sized stars such as Proxima Centauri. Such flares may well sterilize any life that might develop on such a world.

Comments

Will it be tidally locked?

[beanfeast]

The paper gives the planet's orbital period as 9.9 days. I don't know the maths, but I assume the closer a small body is to a large one the quicker it becomes tidally locked . What impact would tidal locking have on the habitability of the planet?

Ross 128 has a high X-ray luminosity

[StupendousMan]

The authors of the paper use measurements of the host star's optical spectrum to infer that it doesn't produce a lot of UV emission, and note that it doesn't have frequent optical flares. That's good news for the habitability of the planet around it, as they point out.

However, they apparently did not note that Ross 128 is a relatively strong X-ray source, as measurements by the ROSAT X-ray satellite show. A colleague of mine worked out the X-ray luminosity of the host star, and it turns out to be not unlike that of the Sun, or even larger. That means that the X-ray flux striking the planet -- which is very close to this host star -- is likely high enough to remove the atmosphere of the planet. No atmosphere means not so interesting a planet, alas.