Around the galaxy subsist stars that have been given a button , and orbit much quicker than the vast majority of their stellar companions . These are know ashypervelocity stars , with some moving quicker than the evasion speed of the Milky Way of around 600 kilometers ( 373 miles ) per second . There is another genius that is almost as speedy , but it does n’t have to worry about that book because it might have breach another . It look like it has a satellite , making this the fastest star system known .

The system of rules was spotted in archival data from MOA ( Microlensing Observations in Astrophysics ) which revealed the potential presence of this belittled star , one - fifth of our Sun , and a large satellite , 29 times the mass of Earth .

“ We think this is a so - called super - Neptune world orbiting a low - masses star at a aloofness that would lie between the eye socket of Venus and Earth if it were in our Solar System , ” lede writer Dr Sean Terry , from the University of Maryland and NASA ’s Goddard Space Flight Center , say in astatement . “ If so , it will be the first satellite ever found orbiting a hypervelocity star . ”

The original observations were from 2011 , and were potential because this brace of objects pass away in front of a more remote star , slightly magnifying it like a glass lens . This is the microlensing effect – a very cool way to see exoplanets but with a drawback . They could n’t mensurate their exact masses , only their proportion , because the distance of the pair is not known . One is about 2,300 times dense than the other .

“ square off the passel proportion is easy , ” said Dr David Bennett , a senior research scientist at the University of Maryland , College Park and NASA Goddard , who co - authored the unexampled paper and led the original study in 2011 . “ It ’s much more hard to calculate their actual volume . ”

The team looked for an objective that might match the star description . They found it in data from theEuropean Space Agency ’s Gaia satellitedated to 2021 . The candidate is this star and first-rate - Neptune pair located 24,000 light - years by , within the Milky Way ’s astronomical bulge .

“ To be sure the fresh identified ace is part of the system of rules that cause the 2011 sign , we ’d like to look again in another year and see if it incite the correct amount and in the ripe direction to confirm it come from the point where we detect the signal , ” Bennett said .

“ If high - resolution observations show that the champion just stays in the same position , then we can tell for sure that it is not part of the arrangement that caused the signal , ” said Aparna Bhattacharya , a research scientist at the University of Maryland , College Park and NASA Goddard who co - author the new paper . “ That would mean the rogue planet and exomoon model is favored . ”

It might be that the star system is actually faster than   600 kilometers per second ( 1.3 million miles per 60 minutes ) . This would be the first known star organisation that finally will leave the Milky Way .

The study is published inThe Astronomical Journal .