Question

Which of the following criteria do astronomers use to classify an object as a planet?

Answer 1

The options to the question are

A) The object orbits a star.

B) Its gravity makes the object spherical.

C) The object clears its orbit of other objects.

D) The object has an atmosphere.

Criteria for a planet

According to the International Astronomical Union (IAU),2006, a planet should fulfill the following three criteria.

1. It must independently orbit the Sun

2. Its gravity must be such that it pulls it into a roughly spheroidal shape

3. It must be large enough to "dominate" its orbit and so clear its orbit of other obstacles.

So the correct answers would be

A) The object orbits a star.

B) Its gravity makes the object spherical.

C) The object clears its orbit of other objects.