 In comparison, the Sun is about 4.6 billion years old and has a surface temperature of 5778 K.

Gliese 876 d is located in an orbit with a semimajor axis of only 0.0208 AU (3.11 million km).At this distance from the star, tidal interactions should in theory circularize the orbit; however, measurements reveal that it has a high eccentricity of 0.207, comparable to that of Mercury in the Solar System.Models predict that, if its non-Keplerian orbit could be averaged to a Keplerian eccentricity of 0.28, then tidal heating would play a significant role in the planet's geology to the point of keeping it completely molten.