TUCSON, Ariz. (AP) — A new planet that breaks all the rules about how and where planets form has been found in orbit of a double star system about 70 light years from Earth in a constellation commonly known as the Northern Cross.
The new planet has a roller-coaster like orbit that swoops down close to its central star and then swings far out into frigid fringes, following a strange egg-shaped orbit that is unlike any other known planet.
“We don’t understand how it could have formed in such an orbit,” said William D. Cochran, head of the University of Texas team that discovered the planet at the same time that a group from San Francisco State found it independently.
The researchers presented papers on the new planet Wednesday at a national meeting of the American Astronomical Society’s planetary division. The new planet is the latest in a series of bodies found in the orbit of stars outside of the solar system, and is part of a quickening effort by astronomers to find distant worlds.
Cochran said the planet orbits the smaller of twin stars in the constellation Cygnus, a prominent stellar grouping known as the Northern Cross. The planet’s star is called 16 Cygni B and the larger companion star is 16 Cygni A.
“Of all the stars you might see in the sky, Cygni B is the most similar to our sun,” said Cochran. It has the same mass and temperature as the sun, but the nearby twin star of Cygni A creates an entirely different type of environment.
Every 250,000 years, Cygni A and B pass within 65 billion miles of each other, a grazing passage by stellar standards. Cochran said the stars are so close that the gravitational tug of Cygni A may have pulled the new planet into its wildly eccentric orbit.
It is unlikely that life exists on the new planet, Cochran said, because it probably is more like the gaseous planets, such as Jupiter or Saturn, than the rocky planets such as Earth or Mars.
The wide-swinging orbit of the planet would also cause extreme fluctuations in temperature, he said.
The University of Texas and San Francisco astronomers found the new planet by studying the movement of Cygni B. They discovered that the star tended to change its speed of motion in a way that could only be explained by the presence of an orbiting satellite. Cygni A has no such motion, said Cochran, suggesting it has no planet.
By some counts, the new planet is the ninth to be found outside the solar system, although some astronomers say there have been up to 11 found. Cochran said the exact number is controversial because not all of the discoveries have been generally accepted as actual planets.