Ross 128 b
Ross 128 b is a confirmed Earth-sized exoplanet, likely rocky, that is orbiting within the inner habitable zone of the red dwarf star Ross 128, at a distance of around 11 light-years from Earth. 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.
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 | |
| Apastron | 0.0511 (± 0.0031) AU |
| Periastron | 0.0475 (± 0.0031) AU |
| 0.0496 (± 0.0017) AU | |
| Eccentricity | 0.036 (± 0.092) |
| 9.8658 (± 0.0070) d | |
| Star | Ross 128 |
| Physical characteristics | |
Mean radius | 1.6+1.1 −0.65R🜨 |
| Mass | 1.8+0.56 −0.43 ME |
| Temperature | 213–301 K (−60–28 °C; −76–82 °F) |
The planet does not transit its host star, which historically made atmospheric characterization very difficult, but this has become possible with the construction of larger telescopes like the James Webb Space Telescope.