This is an artist's conception of a young planet in a distant orbit around its host star. (Photo: NASA/JPL-Caltech)

A giant planet that has been found orbiting its star at 650 times the average Earth-Sun distance has stirred immense confusion in the minds of US astronomers, making them question planet formation theories.

The planet – currently known as HD 106906 b – weighs in at 11 times the mass of Jupiter and is orbiting its star at a massive distance of 60 billion miles – a much further distance than any planet has ever previously been seen orbiting its star.

The planet has been described as unlike anything astronomers have ever seen before.

“This system is especially fascinating because no model of either planet or star formation fully explains what we see,” said Vanessa Bailey, the team’s lead researcher with the University of Arizona’s astronomy department in a news release.

Planets such as Earth, which are located closer to their stars, are believed to be the results of the amalgamation of smaller asteroid-type bodies. The bodies themselves were formed after the gases and heavier elements remaining after the formation of the sun began to flatten and fuse with the help of the sun’s gravity.

However, with planets such as HD 106906 b, the process becomes more puzzling. The process of formation is far too slow for planets of such large mass, which are so far away from their star. However, Baily offered up her suggestion.

“A binary star system can be formed when two adjacent clumps of gas collapse more or less independently to form stars, and these stars are close enough to each other to exert a mutual gravitation attraction and bind them together in an orbit,” Bailey said.

“It is possible that in the case of HD 106906 system the star and planet collapsed independently from clumps of gas, but for some reason the planet’s progenitor clump was starved for material and never grew large enough to ignite and become a star,” she stated.

However, should Baily’s theorizing be correct, it would also induce further questions. The mass ratio of two stars in a binary system, as described by Bailey, is usually no more than 10:1. However, in the case of this new discovery, the mass ratio is over 100:1 – a correlation which could be deemed almost impossible under current theories of planet formation.

The findings are to be published in The Astrophysical Journal Letters under the title “HD 106906 b: A Planetary-mass Companion Outside a Massive Debris Disk.”

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Astronomers discover infernal earth-like planet that ‘shouldn’t be’

This artist's rendition released NASA October 30, 2013 shows Kepler-78b orbiting its parent star. (AFP/NASA)

The space scientists are baffled after finding the first ever Earth-sized planet, which has the same density as our home world, and violates all known planetary formation theories by its existence.

The discovery of Kepler-78b was made by two separate groups of astronomers in the US and Switzerland, who were analyzing data from NASA’s Kepler Space Telescope.

The new planet orbits a sun-like Kepler-78 star in the Cygnus or Swan constellation some 400 light years away from Earth.

The scientists say that Kepler-78b is unique as it’s the first known Earth-sized planet, which has a density similar to Earth.

Despite being twice as heavy, it’s just 20 per cent larger than Earth and is believed to be composed of the same rock and iron as our home world.

But this is where the similarities end as the astronomers stressed that life is impossible on Kepler-78b, which Andrew W. Howard from the University of Hawaii described “as one of the most hellish” places ever discovered.

The planet is a lava world where the surface temperatures exceed 1000 Celcius, “well above the temperature where rock melts,” Howard told the New York Times.

Such extreme conditions are caused by Kepler-78b’s super tight orbit, which overturns the existing knowledge on planetary formation.

The planet circles around its star in just eight and a half hours at a distance of less than a million miles (around 1.6 million kilometers). By contrast, Earth is 93 million miles (around 150 million kilometers) away from the sun, completing a full circle around it in 365 days.

According to current theories, Kepler-78b couldn’t have formed so close to its star as its orbit would’ve been inside the sun when the system was taking shape.

“It couldn’t have formed in place because you can’t form a planet inside a star. It couldn’t have formed further out and migrated inward, because it would have migrated all the way into the star. This planet is an enigma,” Dimitar Sasselov, a member of Dr. Pepe’s team, told the Harvard-Smithsonian Center for Astrophysics (CfA) website.

Another CfA astronomer, David Latham, acknowledged that modern science doesn’t “know how it formed or how it got to where it is today,” calling Kepler-78b “a complete mystery.”

However, Latham stressed that the newly discovered planet “isn’t going to last forever.”

In three billion years, the gravitational tides will draw Kepler-78b close to the sun and it’ll eventually be ripped part.

Kepler-78b is one of more than 150 planets, which NASA’s Kepler Space Telescope spotted by registering dimming of the starlight when a planet passes in front of it.

The spacecraft was launched in 2009, but went out of order this May, with the US Space Agency saying that it won’t be making attempts to resume its operations.

But the amount of data on exoplanets (planets outside the Solar system), which Kepler managed to collect, will take several years for the astronomers to analyze.

 

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