A team of researchers has discovered a temperate Earth-sized planet orbiting an inactive dwarf star. The planet designated Ross 128 b was discovered by a team working with the High Accuracy Radial velocity Planet Searcher (HARPS) at the La Silla Observatory in Chile.
The discovery was detailed in a paper entitled “A temperate exo-Earth around a quiet M dwarf at 3.4 parsecs” published in the Journal of Astronomy & Astrophysics
Ross 128 b is 11 light-years from Earth and orbits its star every 9.86 days. The researchers estimate that temperatures on the surface of the planet likely range from approximately -60 to 20°C. To put that into context, one of the coldest places on Earth is on the East Antarctic Plateau in Antarctica. On a high ridge in this desolate part of the world, temperatures have been found to reach as low as -93.2°C.
Although there are signs that Ross 128b could be habitable, researchers have been careful to avoid concluding that it is just yet. Their scepticism is as a result of the planet not perfectly adhering to current habitable zone models.
“Using theoretically motivated albedos, the Kopparapu et al. (2017) criteria place the planet firmly outside the habitable zone, while Kopparapu et al. (2013), Yang et al. (2014), and Kopparapu et al. (2016) find it outside, inside and just at the inner edge of the habitable zone. The precise location of the inner edge is therefore still uncertain,” explained researchers. “The habitable zone most likely will not be firmly constrained until liquid water is detected (or inferred) at the surface of many planets. Meanwhile, it is probably preferable to refer to Ross 128 b as a temperate planet rather than as a habitable zone planet.”
Although Proxima Centauri is still the closest Earth-like planet to our solar system at 4.25 light-years, Ross 128 b could soon (cosmically speaking )claim that title. Currently, Ross 128 b is 11 light-years away. However, it’s not stationary. The planet is moving closer to Earth and will overtake Proxima Centauri as our closest Earth-like neighbor in approximately 79,000 years.