Which of the following criteria do astronomers use to classify an object as a planet? The object orbits a star. Its gravity makes the object spherical. The object has an atmosphere. The object clears its orbit of other objects.

the object orbits a star

Its gravity makes the object spherical.

The object clears its orbit of other objects.

The criteria that astronomers use to classify an object as a planet is Its gravity makes the object spherical.

Explanation:

There are three principal criteria to determine if an object can be considered a planet:

* It must independently orbit the Sun

* It must have enough mass so that gravity pulls it into a roughly makes it take a spheroidal shape

* It must be large enough to "dominate" its orbit, it must be bigger than any object that crosses it.