Even by celestial standards, the span between a newly found suspected baby planet and its host star is astronomical — 7.5 billion miles, which is about twice as far as Pluto orbits the sun.
To date, only one other extrasolar planet is farther from its host star as the fledgling world circling TW Hydrae, a small red dwarf located about 176 light-years from Earth. That would be probably be Fomalhaut b, astronomer John Debes, with the Space Telescope Science Institute, wrote in an email to Discovery News.
Scientists are at a loss to explain how the planet, which is believed to be six- to 28 times as big as Earth, could exist.
For starters, the host star is only about 8 million years old, which was believed to be too young to support planets. It also is small, about half as massive as the sun. Computer models show that a planet 7.5 billion miles from its parent star would take 200 times longer to form than a planet positioned about where Jupiter is in our solar system.
Jupiter, which took about 10 million years to form, is around 500 million miles from the sun.
The baby planet was detected indirectly from a telltale gap in a 41-billion-mile wide ring of gas and dust circling TW Hydrae. The gap is believed to be due to the growing planet gravitationally sweeping up material that is then incorporated into the planet.
Astronomers used the Hubble Space Telescope for their survey.
Debes says he and his team were surprised by the finding:
As to why this particular star caught his eye, Debes had this comment:
The research is published in The Astrophysical Journal.
Image credit: NASA, ESA, J. Debes (STScI), H. Jang-Condell (University of Wyoming), A. Weinberger (Carnegie Institution of Washington), A. Roberge (Goddard Space Flight Center), G. Schneider (University of Arizona/Steward Observatory), and A. Feild (STScI/AURA)