The Milky Way is massive that it has many stars in it. Most of its stars have been created within itself. However, some stars in the Milky Way have been taken from another galaxy.
The stars that are said to come from another galaxy could be found at the farthest reaches of the Milky Way. The stars are around 300,000 light years away from the Earth. They are found almost outside of the Milky Way's spiral arms.
The stars are said to have come another galaxy called the Sagittarius dwarf. The stars are also said to have been part of a stream of stars that stretch out into space. This stretch is about 10 million light years across, which makes it ten times the width of the whole Milky Way.
Lead author Marion Dierickx from the Harvard-Smithsonian Center for Astrophysics has said that the stream of stars is still not as big as the one that is anticipated to be much even bigger than it. This stream of stars might have likely come from the Sagittarius dwarf. It is one of the dwarf galaxies that surround the Milky Way.
The Sagittarius dwarf revolves around the Milky Way. As it revolves around it, gravity from the Milky Way is slowly pulling the dwarf galaxy apart. In that span of time the Milky Way has taken a number of stars away from it, with some of them drifting in space while others have become part of the Milky Way, according to the Harvard-Smithsonian Center for Astrophysics' site.
To test out how the stars were taken, Dierickx together with Harvard theorist Avi Loeb created a model that showed how the Sagittarius dwarf has moved, as Science Daily reports. They have created various situations to find out how exactly the Milky Way has taken some of its stars. Over a period of time, the dwarf galaxy began to lose about one third of its stars as well as its dark matter to the Milky Way's gravitational pull.
The result has been three streams of stars coming all the way from the Milky Way's center to its edges. This shows that the nearby dwarf galaxies might lose more of its stars and material to the Milky Way in the future. The process will go on as some stars in the Milky Way are taken from another galaxy. A study has found that the Moon is older than first thought.
