A group of stars located a few thousand light-colored - years away all seem to be moving at the same speed around the Milky Way but lag behind the rest of the stuff in the galaxy . The team behind this young research believe the stellar current used to be its own galaxy before it was ripped aside and cannibalized by the Milky Way . The field of study is published inNature Astronomy .
The stellar stream ( and its original galaxy ) has been nickname Nyx , after the Greek goddess of the Night . To bring out the stream , the team apply sophisticated algorithms to stellar maps produce by theEuropean Space Agency ’s Gaia satellite , which contain information on the position and speed of 1 billion stars . They then used the software to find related group of stars and discover 232 that were imprison together .
Due to gravitative disturbance , it is potential for groups of stars in the Milky Way to be a few ten of kilometer per indorsement slower than the median rotational speed of the galax . However , the stars in the Nyx stream were 90 km ( 56 miles ) per second slow – too much to be just moot a wearisome chemical group . The information suggests this was not an anomaly and that these objects are in all probability colligate to each other .
By combining these results with simulations of the phenomena , the squad believe that Nyx might have been a dwarf extragalactic nebula absorb by our own about 1 billion years ago . The data analytic thinking also suggests that a 2d group called Nyx-2 might exist . The team plan to further investigate these stars and their chemical physical composition in club to rule out if their makeup is logical with whiz that organize together in a dwarf galaxy .
While there are still uncertainties about the nature of Nyx , this would n’t be the first galaxy our whitish Way has cannibalized . It also wo n’t be the last . Gaia alone has brought to calorie-free grounds of past mergers such as theAntlia-2dwarf and theGaia - Enceladus . There are also signs of upcomingmergers with the Milky Way .
If Nyx is confirmed , it will be in good company .
