Larissa 

Discovered in 1989 by Stephen Synnott, Larissa is a moon of Neptune and lies about 48,800 kilometers (30,300 miles) from the surface. It circles the planet once in 13 hours, 18 minutes. Like many other moons of Neptune, Larissa orbits Neptune in the same direction that the planet rotates and lies close to the equatorial plane.

Physical Data Key Mass Mass Mass Mass compared to that of Earth. Radius Radius Radius Radius compared to that of Earth. Mean Density Average Density. Distance Distance to the planet's center. Magnitude The brightness of a star or object.

Orbital Data Key Rotational Period Number of days to make one complete rotation. Orbital Period Number of days to obital the planet. Mean Orbital Velocity Average obital speed. Orbital Eccentricity Eccentricity. Orbital Inclination The tilt of the moon or planet. Escape Escape Velocity. Albedo Visual geometric albedo.