A newly discovered dwarf planet called 'Ammonite' (2023 KQ14) has been spotted in the outer solar system, and it could be another nail in the coffin for the Planet Nine hypothesis.

Its size is estimated to be a bit smaller than Ceres, which is the smallest of the solar system’s five recognized dwarf planets and has a diameter of about 590 miles (950 km).

Using the James Webb Space Telescope, astronomers have discovered the smallest brown dwarfs ever seen with the potential to form planets and surrounded by mysterious molecules.

U.S. astronomers hunting for "Planet Nine" have instead stumbled on what appears to be a new dwarf planet in the solar system's outer reaches.

Barnard's star, located in the direction of the constellation Ophiuchus, is a red dwarf, the smallest type of regular star. Its mass is about 16% of the sun's and it is far less hot.

Barnard’s star, located in the direction of the constellation Ophiuchus, is a red dwarf, the smallest type of regular star. Its mass is about 16% of the sun’s and it is far less hot.

Pluto, the largest of those dwarf planets, has a diameter of about 1,477 miles (2,377 km). The mass of 2017 OF201 is estimated to be about 20,000 times smaller than Earth's and 50 times smaller ...