Two giant planets have been observed performing a “gravitational dance”, astronomers have revealed.
The orbs were spotted 800 light-years away in the constellation of Hercules, scientists from the Wide Area Search for Planets (WASP) consortium said.
The planets, named WASP-148b and WASP-148c, orbit a sun-like star and can "feel each other’s gravity”.
This means faster-orbiting WASP-148b can speed up and slow down as it overtakes WASP-148c on the inside - a phenomenon which looks like dancing, astronomers said.
Professor Andrew Collier Cameron, of the University of St Andrews and WASP team member, said: “This is the first time we’ve found a pair of giant planets interacting so closely."
He added: "It’s exciting to be able to follow their dance from the ground.”
An international team of scientists, which also included scientists from The Open University (OU) and University of Warwick, made the discovery using instruments on Earth rather than with space telescopes.
WASP-148b was identified by a range of instruments installed at the Roque de los Muchachos Observatory in La Palma, Canary Islands.The star system was then observed with an instrument known as SOPHIE at the Observatoire de Haute-Provence in France.
They found WASP-148b, which is about the size and mass of Saturn, takes about 8.8 days to circle its host star while the orbital period for WASP-148c, thought to have a mass half that of Jupiter, is around 34.5 days.
Analysis revealed both WASP-148b and WASP-148c orbit in the same plane, just like the planets in the Solar System.
The findings are published in the Astronomy & Astrophysics journal.
