Astronomers have long known that stars are born in star clusters. It is believed that the sun was born with a group of other star siblings. However, the sun’s star cluster was pulled apart as it moved through the Milky Way galaxy. It is expected that each star in the sun’s birth cluster will have the same chemical composition.
So, in a quest to map sun’s lost siblings, an Australian-led team of astronomers has reportedly unlocked the DNA of more than 340,000 stars in the Milky Way. As part of the Galactic Archaeology survey (GALAH), which was launched in late 2013, scientists are aiming to map the chemical signatures of over 1 million stars to uncover the mystery behind the evolution and formulation of galaxies.
For the purpose of the study, the research team collected the light of over 340,000 stars from the HERMES spectrograph at the 3.9-meter (13-foot) Anglo-Australian Telescope at the Australian National University’s Siding Spring Observatory. The telescope first tracks starlight and then feeds it into the spectrograph, which splits the light into spectra. The researchers examine the locations and the size of the dark lines in the spectra to identify each star’s chemical composition.
HERMES scientist Gayandhi De Silva, from the University of Sydney, said that mapping the chemical makeup of individual stars will help them identify which ones were formed at the same time. The information will also help unravel the mystery of the universe’s evolution after the Big Bang 14 billion years ago.
De Silva said that the data collected will enable such discoveries as the original star clusters of the Galaxy, including the Sun’s birth cluster and solar siblings. She added that there is no other dataset like this ever collected anywhere else in the world.
The GALAH team is looking forward to comparing its data with the data obtained by the European Gaia satellite, which has been examining the Milky way’s 1.6 billion stars.