Ross 128 b is a closely orbiting planet, with a year (rotation period) lasting about 9.9 days.[29][30] At that close distance from its host star, the planet is most likely tidally locked, meaning that one side of the planet would have eternal daylight and the other would be in darkness.[31][32] Near-infrared high-resolution spectra from APOGEE have demonstrated that Ross 128 has near solar metallicity; Ross 128 b therefore most likely contains rock and iron. Furthermore, recent models generated with these data support the conclusion that Ross 128 b is a "temperate exoplanet in the inner edge of the habitable zone."[33]