Helene 

Discovered in 1980 by P. Laques and J. Lecacheus through ground based observations, Helene is a moon of Saturn that is often referred to as a Dione Trojan satellite because its orbit is the same as Dione's orbit. The only difference is that Helene is 60 degrees ahead.

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.