A star is seen to have two transiting planets. Planet 1 transits every 3 months, and Planet 2 transits every 15 months. What can we infer about their orbits?
A)Planet 2's orbit is more eccentric than Planet 1's.
B)Planet 1's semimajor axis is larger than Planet 2's.
C)Planet 1's orbit is more eccentric than Planet 2's.
D)Planet 2's semimajor axis is larger than Planet 1's.

Question

Quizplus · Accepted Answer

The orbital period of a planet (the time it takes to complete one orbit around its star) is directly related to the size of its orbit, as described by Kepler's third law of planetary motion. A longer orbital period, such as that of Planet 2 (15 months), indicates that it has a larger semimajor axis compared to Planet 1, which has a shorter orbital period of 3 months. This means Planet 2 is further from the star than Planet 1.

A Star Is Seen to Have Two Transiting Planets