The discovery of a giant planet orbiting a very young star some 450 million light years from the Earth has forced astronomers to rethink their long-held view that larger planets take longer to form.
“CI Tau b” is at least eight times larger than Jupiter and orbits a two million-year-old star in the constellation Taurus.
“For decades, conventional wisdom held that large Jupiter-mass planets take a minimum of 10 million years to form,” said lead author Christopher Johns-Krull from Rice University in Texas.
“That’s been called into question over the past decade, and many new ideas have been offered, but the bottom line is that we need to identify a number of newly formed planets around young stars if we hope to fully understand planet formation,” he added.
The study, involving a dozen researchers from Rice, Lowell Observatory, University of Texas at Austin, NASA and Northern Arizona University, made the peer-reviewed study available online this week.
“CI Tau b” orbits the star CI Tau once every nine days.
The planet was found with the radial velocity method — a planet-hunting technique that relies upon slight variations in the velocity of a star to determine the gravitational pull exerted by nearby planets that are too faint to observe directly with a telescope.
“This result is unique because it demonstrates that a giant planet can form so rapidly that the remnant gas and dust from which the young star formed, surrounding the system in a Frisbee-like disk, is still present,” said co-author Lisa Prato of Lowell Observatory.
“Giant planet formation in the inner part of this disk, where CI Tau b is located, will have a profound impact on the region where smaller terrestrial planets are also potentially forming,” she added.