Ross 128 b
Artist's impression of the planet Ross 128 b, with the star Ross 128 in the background. | |
| Discovery | |
|---|---|
| Discovered by | Xavier Bonfils |
| Discovery date | November 15, 2017 |
| Radial velocity | |
| Orbital characteristics | |
| 0.049640±0.000004 AU | |
| Eccentricity | 0.21+0.09 −0.10 |
| 9.8556+0.0012 −0.0011 d | |
| Semi-amplitude | 1.41±0.14 m/s |
| Star | Ross 128 |
| Physical characteristics | |
| 1.6+1.1 −0.65 R🜨 (predicted) | |
| Mass | ≥1.40±0.13 M🜨; 1.8+0.56 −0.43 M🜨 (predicted) |
| Temperature | 213–301 K (−60–28 °C; −76–82 °F) (equilibrium) |
Ross 128 b is a confirmed Earth-sized exoplanet, likely rocky, that is orbiting near the inner edge of the habitable zone of the red dwarf star Ross 128, at a distance of 11.007 light-years (3.375 parsecs) from Earth in the constellation of Virgo. The exoplanet was found using a decade's worth of radial velocity data using the European Southern Observatory's HARPS spectrograph (High Accuracy Radial velocity Planet Searcher) at the La Silla Observatory in Chile. Ross 128 b is the nearest exoplanet around a quiet red dwarf, and is considered one of the best candidates for habitability. The planet is only 35% more massive than Earth, receives only 38% more starlight, and is expected to be a temperature suitable for liquid water to exist on the surface, if it has an atmosphere.
The planet does not transit its host star, which makes atmospheric characterization very difficult.