New Planet Puts Scientists at Odds over Planet Formation Theory
18 June 2013
A new planet is forming unusually far from its host star, surprising evidence from the Hubble Space Telescope has revealed, putting scientists at odds over established theories on planet formation, NASA has reported.
The planet, located 176 light years away from our planet in the Hydra the Sea Serpent constellation, is forming 7.5 billion miles (12.1 billion km) away from its star, approximately twice the distance Pluto is from the sun, researchers at the Space Telescope Institute in Baltimore, Maryland found. Of all the planets known outside the solar system, numbering nearly 900, this is the first to be orbiting at such a huge distance from its star, NASA says.
The researchers observed in near-infrared light the TW Hydrae red dwarf star with Hubble's Near Infrared Camera and Multi-Object Spectrometer (NICMOS). After comparing the images with data from Hubble's archives and optical and spectroscopic observations from Hubble's Space Telescope Imaging Spectrograph (STIS), they noticed a protoplanetary disk of dust and gas circling around an orbit. Within the disk, which is 41 billion miles in width, they discovered a strange gap, 1.9 billion miles wide, making the scientists believe it was the location of a new unseen planet that is sweeping up the dust nearby with its own gravitational pull, forming a lane in the disk.
The planet is between six and 28 times larger than the Earth, which means it is actually quite small. Given the large distance from TW Hydrae, the researchers presume it has a slow-moving orbit.
The widely accepted theory is that it takes tens of millions of years for a planet to form. TW Hydrae is just eight million years old, which suggests that it is an unlikely star to host a planet. According to another theory contradicting with prevailing beliefs, planets form after a piece of a disk becomes too gravitationally unstable and collapses on itself, which would allow a planet to grow in just a few thousand years.