Four planets secured in an ideal rhythm around a nearby star are inclined to be pinballed around their solar system if their sun eventually dies, according to a study led by the University of Warwick that peers into its own future.
Astronomers have modelled the way the change in atmospheric forces in the system as a result of the star getting a white dwarf will induce its planets to fly loose out of their orbits and bounce off each other’s gravity, such as balls bouncing off a bumper in a game of pinball.
In the process, they’ll knock nearby debris in their dying sun, giving scientists fresh insight into how the white dwarfs with polluted atmospheres that we see today originally evolved. The decisions by astronomers from the University of Warwick and the University of Exeter are published in the Monthly Notices of the Royal Astronomical Society.
The HR 8799 system is 135 light years off and comprises a 30-40 million year old A type star and four unusually massive planets, all over five times the mass of Jupiter, orbiting very close to one another. The system also comprises two debris disks, inside the orbit of the innermost planet and the other outside the outermost. Recent studies have shown that the four planets are locked in a perfect rhythm that sees each one finishing twice the orbit of its neighbour: therefore for every orbit the furthest completes, the next closest completes two, another completes four, while the nearest finishes eight.
The group from Warwick and Exeter decided to learn the ultimate destiny of the system by creating a model that allowed them to play’planetary pinball’ with the planets, exploring what may cause the perfect rhythm to destabilise.
They determined that the resonance that locks the four planets is very likely to hold firm for the next 3 billion years, despite the effects of Galactic tides and near flybys of other celebrities. However, it breaks after the star enters the stage where it becomes a red giant, as it will expand to several hundred times its current size and eject nearly half its mass, ending up as a white dwarf.
The planets will subsequently start to pinball and become an extremely chaotic system in which their movements become quite uncertain. Even shifting a planet’s position with a centimetre at the start of the procedure can dramatically alter the outcome.
Lead author Dr Dimitri Veras from the University of