Astronomers have discovered a star in the galaxy of the Milky Way with a chemical composition unlike any other stars in our galaxy. This chemistry was seen in a small number of stars in dwarf galaxies that orbit the Milky Way. This suggests that the star was part of a dwarf galaxy that merged in the Milky Way.
In LAMOST (Large Sky Area Multi-Object Fiber Spectroscopic Telescope) survey data, researchers noticed J1124 + 4535 star for its unusual chemical composition. Initial observations showed that J1124 + 4535, located in Suzorye & # 39; and Ursa Major (the Big Dipper), have a low content of some elements, such as magnesium. The following observations high dispersion spectrograph at Subaru telescope confirmed low magnesium levels, but found relatively high levels of europium. This is the first case in which the element ratio, as noted in a star in the Milky Way.
Stars form from clouds of interstellar gas. Value of the parent element clouds give the observed chemical signature on stars formed in this cloud. Since stars formed close to each other have similar ratios of the elements. The composition of J1124 + 4535 does not match the other stars in the Milky Way, indicating that it should be formed in a different place.
The chemical signature similar to J1124 + 4535 are observed in some of the stars in the dwarf galaxies that orbit the Milky Way. Galaxy evolution models and simulations show that galaxies like the Milky Way grow by absorbing nearby dwarf galaxies. Thus, it makes sense that J1124 + 4535 was born in the now extinct dwarf galaxy that merged in the Milky Way.
The National Institute of Natural Sciences. .