Image: ESO / Digitised Sky Survey
Astronomers have solved a longstanding mystery about the ancient collision of the milky Way with another galaxy. Scientists were able to determine a relatively precise time of a huge catastrophe, having ascertained the age of the star that has been affected by a large-scale event. This publication reports Science Alert.
The researchers studied the star Nu Indi (HD 211998), which is only 94 light years from Earth in the constellation of Indian. In size it exceeds the Sun three times, but her weight is only 85 percent of the solar. Although the star originated in the milky Way, according to the space telescope Gaia, its movement through the galaxy was changed by collision with a star system Gaia Sausage. It is the largest dwarf galaxy, which has ever faced the milky Way.
Thus, the age of the star imposes a restriction on how long since merged galaxies. A key feature that helps to identify the time of occurrence of the luminaries is the metallicity — the content of chemical elements heavier than hydrogen and helium. These elements first appeared in the oldest stars, which then exploded as a supernova. From the remnants became the stars of the next generations. Nu Indi contains only three percent of iron of the total amount of this metal in the Sun that indicates that HD 211998 quite old.
Astronomers have refined the age of the star by measuring the frequency of the brightness change due to internal processes and age. According to the space telescope TESS, Nu Indi arose 11 billion years ago. A clash of galaxies was to begin the 11.6-13.2 billion years ago, it could affect the star.
Video, photo All from Russia.