An exoplanet counting off the years in an enormous 15 000-year-long orbit has astronomers analysing Hubble images of the double star HD 106906 asking questions about our own planets. The star of this exoplanet would be as far distant from this alien solar system as a theoretical Planet Nine would be from our Sun.
This is empirical confirmation of the presence of equally extensive universes around other stars. Researchers believe that the earth ended up in a "game of celestial pinball" where a moving star's gravitational force altered the orbit structure. It's possible that 4.6 billion years ago a passing star had a similar effect on our solar system.
There are circumstantial indications that a five times as massive planet – called Planet Nine – could lie in the abyss. In fact, the planet found in HD 106906 is creeping around a very wide orbit that brings it 800 times farther from what was theorized.
"This is the first time that scientists have been able to calculate the rotation of a huge Jupiter-like plant that circles far away from its host stars and visible waste disk," said the paper's lead author, Meiji Nguyen of the University of California, Berkeley, "This system draws a potentially unique comparison with our solar system....It's very widely separated from its host stars on an eccentric and highly misaligned orbit, just like the prediction for Planet Nine. This begs the question of how these planets formed and evolved to end up in their current configuration."
HD 106906 was discovered in 2013 with the Magellan Telescopes at the Las Campanas Observatory in the Atacama Desert of Chile. Hubble's team was shocked to find that the distant world has an extreme orbit which is very warped. The debris disks themselves appear exceptionally unique, possibly because of the gravitational pull of the wayward planet.
How did the exoplanet get into such a far-distant and unusually inclined orbit? The dominant hypothesis is that it evolved far closer to its star, about three times the distance the Earth is from the Sun.
In a 2015 report, Paul Kalas of the University of California led a team which found circumstantial evidence for the planet's unusual orbit. The system's debris disk is highly asymmetric rather than a spherical "pizza pie" distribution. This asymmetry is reinforced every time the planet comes nearer to a binary star.
Planet Nine could have been formed in the inner solar system and kicked off through interactions with Jupiter. To date, scientists have only circumstantial proofs for Planet Nine. "It's as if we have a 4.6 billion-year-old time machine," Kalas says.
"One question you could ask is: Does the planet have its own debris system around it? Does it capture material every time it goes close to the host stars? And you'd be able to measure that with the thermal infrared data from Webb," said Robert De Rosa of the European Southern Observatory in Santiago, Chile. "Also, in terms of helping to understand the orbit, I think Webb would be useful for helping to confirm our result."