Astronomers Discover Star That Witnessed Milky Way’s Cannibalistic Past

Astronomers have spotted a star that’s linked to the violent past of Earth’s neighborhood, the Milky Way galaxy. According to the astronomers, the star holds signs that Milk Way once devoured a large satellite galaxy following a collision billions of years ago.

The star that became the focus of a new study by astronomers has been identified as Nu Indi. It lies about 94 light-years from Earth and can be found in the constellation Indus. The study carried out by the astronomers on the star was recently published in the journal Nature Astronomy.

Unlike other stars in the galaxy, Nu Indi is not rich in metal. Also, even though it’s three times bigger than the Sun, it has less mass than the giant star. Through a scientific process known as spectroscopic analysis, which allowed the astronomers to study the star’s chemical composition, they discovered that Nu Indi was formed inside the Milky Way. However, other data indicate that the star’s movement was affected by a massive cosmic event that happened within the galaxy.

According to the astronomers, soon after the star was formed, Milky Way collided with a nearby satellite galaxy known as Gaia-Enceladus. The impact from the collision affected the movement of Nu Indi, causing it to deviate from its normal orbit when it was first formed.

“Since the motion of Nu Indi was affected by the Gaia-Enceladus collision, the collision must have happened once the star had formed,” astrophysicist William Chaplin, one of the authors of the study, said in a statement.

According to the astronomers, Gaia-Enceladus is currently the largest satellite galaxy devoured by Milky Way. Since they believe the collision between the two galaxies happened shortly after the birth of Nu Indi, the astronomers analyzed previous studies to determine the star’s age.

After determining that the star is about 9 billion years old, the astronomers estimated that the collision and merger of Gaia-Enceladus and Milky Way may have occurred between 11.6 and 13.2 billion years ago. This strongly suggests that the collision occurred right after the universe’s formation.

For the astronomers, studying the collision between Gaia-Enceladus and Milky Way could provide valuable information regarding the evolution of Earth’s neighborhood.

“Because we see so many stars from Gaia-Enceladus, we think it must have had a large impact on the evolution of our Galaxy,” the study’s co-author Ted Mackereth explained. “Understanding that is now a very hot topic in astronomy, and this study is an important step in understanding when this collision occurred.”