New astronomic guidelines say that Pluto is no longer a planet.

The International Astronomical Union on Friday laid out a three-class planetary system that strips Pluto of its planetary status and cuts the number of planets in the solar system from the previous nine to eight.

It is the first time astronomers have officially defined the qualifications of a “planet.”

The new astronomical guidelines say that a “planet” is “a celestial body that is in orbit around the sun, has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a ... nearly round shape, and has cleared the neighborhood around its orbit.”

Accordingly, Pluto has been classified as a “dwarf planet” or "minor planet" along with the icy object Xena and the asteroid Ceres.

Some two-thousand-500 astronomers from 75 countries attended the Union’s general meeting, which opened last week.