Astronomers find two of the Milky Way’s earliest building blocks

Research scientists at the Max Planck Institute for Astronomy have identified two structures named “Shakti” and “Shiva” as potential ancestors of the Milky Way galaxy. Published in the Astrophysical Journal, the discovery suggests that these structures are remnants of galaxies that merged with an early version of the Milky Way around 12 to 13 billion years ago, contributing to its initial growth.

The institute likens the discovery to archeologists identifying traces of an initial settlement that eventually evolved into a modern city. While it’s currently impossible to determine which stars originated from which predecessor galaxy, most stars retain properties linked to their original galaxy’s speed and direction.

Using basic physics principles, researchers found groups of stars with similar, uncommon values for energy and angular momentum, indicating possible merger remnants. Additionally, the low metal content of these stars suggests they existed during the Milky Way’s early stages.

The availability of large, high-quality datasets from the European Space Agency’s Gaia satellite, launched in 2013, has significantly aided this research. By combining Gaia data with stellar spectra from the Sloan Digital Sky Survey, which provides information on stars’ chemical composition, researchers identified the two structures.

Further surveys promise to provide more data, including precise distances and spectra, which will help astronomers confirm whether Shakti and Shiva indeed represent glimpses into the Milky Way’s earliest history.

Source – CGTN