How can planet with four suns exist? Astronomers' latest puzzle

Amateur planet hunters find new world, PH1, the first of its kind ever seen

LAST UPDATED AT 15:14 ON Tue 16 Oct 2012

TWO amateur astronomers have stunned the scientific community with the discovery of a planet from which it would be possible to see four suns. The distant body, located less than 5,000 light years from earth, orbits one pair of stars and is circled by a second pair, a type of solar system previously unknown to scientists.

Six circumbinary planets - planets that orbit two suns - have been documented but none of those are orbited by other stars.

The planet was discovered by 'armchair astronomers' Kian Jek, from San Francisco, California, and Robert Gagliano, from Cottonwood, Arizona and is named PH1, after the website used to find it: Planethunters.org.

Planet Hunters is a project run by Yale University which enlists the public to look for signs of new planets. Using data collected by Nasa's Kepler space telescope, visitors identify dips in the output of stars caused by their light being blocked by 'transits' of orbiting stars.

By doing so scientists hope to find evidence of new worlds, particularly of Earth-like planets orbiting stars similar to our Sun.
Debra Fischer, a professor of astronomy at Yale, and one of the founders of the Planet Hunters project, told the Daily Mail that PH1 "might have been entirely missed if not for the sharp eyes of the public".

Jek and Gagliano's observations were confirmed by a team of UK and US scientists at Keck Observatory, Hawaii. The scientists identified PH1 as a gas giant, slightly larger than Neptune, with a radius about six times that of Earth.

The planet's temperature is thought to be far too hot to harbour life: scientists estimate it ranges from a minimum of about 251 degrees Celsius to a maximum of 340 degrees.

Dr Chris Lintott of Oxford University told The Independent: "It's fascinating to try and imagine what it would be like to visit a planet with four suns in its sky, but this new world is confusing astronomers."

It is not at all clear how the planet managed to form, and remain in stable orbit, whilst being pulled at by the gravity of its many stars.

"All four stars pulling on it creates a very complicated environment," Dr Lintott said. "Yet there it sits in an apparently stable orbit."

Yale astronomer Meg Schwamb explained that even the circumbinary planets are extremes of planet formation: "The discovery of these systems is forcing us to go back to the drawing board to understand how such planets can assemble and evolve in these dynamically challenging environments." · 

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