James Owenfor National Geographic News
April 3, 2008
The youngest planet ever detected has been found developing inside a distant "womb of gas," scientists have announced.
The embryonic planet may only be a few hundred years old, providing a unique look at how planets are made, according to a team of astronomers led by Jane Greaves of the University of St. Andrews in Scotland.
"We were amazed when we found it," Greaves said, noting that the next youngest confirmed planet is ten million years old.
The newfound protoplanet, named HL Tau b, was discovered taking shape about 520 light-years away in the constellation Taurus.
HL Tau, the parent star, is itself in its infancy, since it's believed to be less than a hundred thousand years old. Our own sun, by comparison, has been blazing for more than 4.5 billion years.
The new planet is a "distinct orbiting ball of gas and dust, which is exactly how a very young protoplanet should look," Greaves said in a statement.
"The planet will probably take millions of years to settle down into its final form," she said. "So we really are seeing it very early—even a bit like the first cells that make up a human embryo in the womb."
Despite its youth, the developing world is already a healthy size as planets go, Greaves noted.
"The protoplanet is about 14 times as massive as Jupiter and is about twice as far from HL Tau as Neptune is from our sun," she said.
That means HL Tau b will likely grow into a gas giant resembling a larger version of Jupiter.
Greaves' team made the surprise find while studying the protoplanet's parent star using radio telescopes at the Very Large Array (VLA) in New Mexico and the Jodrell Bank Observatory in England.