By Will Dunham WASHINGTON, Feb 14 (Reuters) - Astronomers have observed a planetary system that challenges current planet ...

The fourth planet in the system is a rocky world, while the second and third ones are gas planets.

Their observations of a faint, cool M-dwarf star called LHS 1903 revealed a system with a rocky world at its outer edge. LHS ...

Astronomers have spotted an unusual 'inside-out' planetary system where a rocky world seems to have formed far beyond the realm typically reserved for gas giants.

A planetary system 116 light-years from Earth has a peculiar pattern. It could flip the script on how planets form, scientists say.

At the farthest edges of the solar system, strange objects follow paths that defy easy explanation. This story investigates ...

Astronomers have found a rocky planet where it should not exist, orbiting far from a cool red star. Could this strange ...

The shape of a planet's orbit is one of its fundamental properties, along with its size and distance from its host star. Earth has a nearly circular orbit, but some planets outside our solar system, ...

A young star called V1298 Tau is giving astronomers a front-row seat to the birth of the galaxy’s most common planets. Four massive but extremely low-density worlds orbiting the star appear to be ...

LONDON — The search for an unknown planet in our solar system has inspired astronomers for more than a century. Now, a recent study suggests a potential new candidate, which the paper's authors have ...

Studying the orbits of thousands of exoplanets shows that large planets tend to have elliptical orbits, while smaller planets tend to have more circular orbits. This split coincides with several other ...