Oldest alien planets found - born at dawn of universe
Baku, March 29 (AZERTAC). Two huge planets found orbiting a star 375 light-years away are the oldest alien worlds yet discovered, scientists say. With an estimated age of 12.8 billion years, the host star—and thus the planets—most likely formed at the dawn of the universe, less than a billion years after the big bang. "The Milky Way itself was not completely formed yet," said study leader Johny Setiawan, who conducted the research while at the Max-Planck Institute for Astronomy in Heidelberg, Germany. During a recent survey, Setiawan and colleagues found the signatures of the two planets orbiting the star, dubbed HIP 11952. Based on the team`s calculations, one world is almost as massive as Jupiter and completes an orbit in roughly seven days. The other planet is nearly three times Jupiter`s mass and has an orbital period of nine and a half months.
Setiawan and colleagues found the ancient planets using a technique called radial velocity, in which astronomers watch for periodic wobbles in a star`s light due to the gravitational tugs of orbiting worlds. The discovery indicates that planet formation in the early universe was possible despite the fact that stars in existence back then were metal-poor—the astronomy term for stars lacking in elements heavier than hydrogen and helium. The idea of planets springing from such a stellar makeup runs counter to a widely accepted theory called the accretion model, which says that heavy elements are needed to form planets.
"To verify this issue, it is necessary to do a planet-search survey around metal-poor stars," Setiawan said. Despite the newfound planets` longevity, it`s unlikely the worlds will survive for another 13 billion years. The parent star will soon transform into a red giant, Setiawan said, one of the last stages of a sunlike star`s life. During this stage, the star will swell in size and most likely engulf any nearby planets.
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