Runaway planet found orbiting ultra-fast star for first time – it’s flying through Milky Way 4X faster than lightning

ASTRONOMERS may have just found the fastest exoplanet system in the galaxy - a super-Neptune world orbiting a hypervelocity star.

The pair are thought to be moving at roughly 1.2million mph. That's more than four times the speed of lighting.

Though they could be moving much faster, at speeds that could one day launch them through the galaxy and into deep-space, according to a new , published in The Astronomical Journal.

"We think this is a so-called super-Neptune world orbiting a low-mass star at a distance that would lie between the orbits of Venus and Earth if it were in our solar system," explained Nasa researcher, Sean Terry, who led the study.

"If so, it will be the first planet ever found orbiting a hypervelocity star."

A hypervelocity star is an ultra-fast star that researchers believe has brushed past the supermassive black hole at the centre of our galaxy, the Milky Way.

But the star, unlike our Sun, is weak - which crushes any hope of finding life on this speedy planet.

The pair were first discovered in 2011 about 24,000 light-years away.

Although researchers at the time didn't know what these cosmic objects were.

By comparing their location in 2011 and again in 2021, the team were able to calculate the breakneck speed at which this exoplanet system is travelling.

But that's just 2D motion, researchers noted.

If the pair are also moving toward or away from Earth, then they must be travelling through space even faster.

Their true speed may even be enough to break through the galaxy and fly into intergalactic space.

To do this, celestial objects must reach a speed of over 1.3million mph - or 600km per second.

"To be certain the newly identified star is part of the system that caused the 2011 signal, we'd like to look again in another year and see if it moves the right amount and in the right direction to confirm it came from the point where we detected the signal," said David Bennett, a senior research scientist at Nasa and co-author, who led the original study in 2011.

If the star stays in the same position, then the team will know it's not the same object that was detected in 2011.

In which case, researchers believe it could instead be a rogue planet with an orbiting moon which would be effectively invisible.

Without a star, these cosmic objects - no matter how large - would be too dark, and therefore lost in the inky void of space.