A space RPG campaign I ran one time was set on this tidal-locked world. One side always faces the star it orbits, and the other is a forever midnight frozen waste. The lump on the dark side is a huge pile of frozen hydrogen, captured by the magnetic field from the solar wind.
I was thinking that there would be an advanced civilization of magma-dwelling creatures living in the volume of the planet, but the players never got far enough to interact with them.
A few statistics:
Orbital period: 5.32 earth days
Mean orbital radius: 9.14 Gm
Apparent solar size: 17.2 times earth
Planetary mass: 2.55E+023 Kg
Planetary mean radius: 2140 km
Surface gravity: .38 gee
Magnetic field size: 1.60E+008 m
Field Density, Poles: 3.82E+002 Gauss
Hydrogen snow depth at pole: 80 km
Pressure at the bottom of the hydrogen ice-cap: 26.2 MPa
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