According to Kepler's third law, the square of the planet's period in years is:. Physics & Astronomy

proportional to the cube of its semimajor axis in A.U.

equal to its perihelion distance from the Sun in A.U.

equal to the fourth power of its average temperature in degrees Kelvin.

equal to the square of its aphelion distance in A.U.

inversely proportional to its mass in kilograms.