Scientists in search for sun’s siblings

27/08/2018 Posted by admin

An Australian-led team of astronomers has unlocked the ‘DNA’ of more than 340,000 stars.STAR DNA COULD HELP SCIENTISTS FIND THE SUN’S SIBLINGS

* How do stars form?

Stars are created from clouds of dust and gas – mostly hydrogen and helium – which are pushed together by gravity. The gases heat up, allowing nuclear reactions to begin and release energy. Stars also contain traces of about two dozen chemical elements including oxygen, nitrogen, carbon, aluminium and iron.

* Why do astronomers want to identify the ‘DNA’ of stars?

Astronomers believe that stars are born in clusters. The stars in those clusters share the same chemical makeup, or DNA. However not long after they are “born”, the stars split up from their cluster and spread out across the galaxy. By mapping the DNA of stars astronomers hope to work out which ones were born at the same time, effectively identifying their “brothers” and “sisters” from the cluster. Knowing which stars are related could help shed new light on one of the biggest challenges in science – how the universe formed after the Big Bang nearly 14 billion years ago.

* What did they use?

An Australian-led team of astronomers began working on the Galactic Archaeology survey, dubbed GALAH, in 2013 with the aim of investigating one million stars. Using the HERMES spectrograph and the Australian Astronomical Observatory’s 3.9 metre Anglo-Australian Telescope at Coonabarabran, in the central west of NSW, they’ve examined the light emitted by more than 340,000 stars.

* What did the starlight tell them?

The spectrograph splits the starlight into detailed rainbows, or spectra. The astronomers measured dark lines in the spectra to work out the amounts of chemical elements in each star, in other words, its stellar DNA. They’ve been comparing data collected from each star to find out which ones are “siblings” from the same cluster. While they have managed to find the siblings of some stars, they are still looking for ones closely related to the sun.

* What do they do next?

The GALAH study will continue analysing star DNA and the search for the sun’s siblings. The data collected from the survey will also be compared to the next batch of information due to be released from the European Gaia satellite on April 25. Gaia has been mapping more than 1.6 billion stars in the Milky Way in one of the biggest exercises in mapping the night sky ever conducted.

Australian Associated Press

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