The search for a long lost sibling of our Sun

An international group of astronomers led by scientists from the University of Sydney has analyzed the chemical composition of more than 340,000 stars in the Milky Way. The goal of the study is to look for siblings of our Sun scattered around the galaxy.

The study is part of the Galactic Archaeology with HERMES project, in skroGALAH and just published the first data collected in it. This project was launched at the end of 2013 and aims to better understand the process ofoin the formation and evolution of galaxies. The premise is to examine a million stellar. Astronomers from Europe and Australia are working on it.

Scientists analyze stars for the amount of elementsoin chemicals, such as iron, aluminum and oxygen, whichoThey are located in. This will help determine „DNA” stars. During the analysis, scientists use the HERMES spectrograph on the nearly 4-meter Anglo-Australian Telescope at Siding Spring Observatory.

The data will help determine the origin of stars by showing astronomers how the Universe has changed since timeoin the Big Bang, when it was filled only with hydrogen and helium, to its present state with all the elements thatore found on Earth and whichore are essential for life.

– No other study has been able to measure so many elementalow for so many stars – Said Gayandhi De Silva of the University of Sydney, ktory supervised the work of the astronomerow. – The data will enable discoveries such as the original star clusters of our galaxy, including the cluster where our sun and its siblings were born. There is no other such collection of data – added.

The Sun, like all other stars, was born in a group or cluster, ktora begets thousands of other stars. – Each star in this cluster will have the same chemical composition, something like a „DNA”. These clusters have been torn apart by our galaxy and are now scattered throughout the Milky Way – explained Dr. Sarah Martell of the University of New South Wales in Sydney, who directs the GALAH observations. – The team’s goal is to match „DNA” stars to find their long-lost siblings – added.

Researchers are using a technique called spectroscopy in their work. The light emitted by the stars is collected by the telescope and then passes through an instrument called a spectrograph, whichory splits them into a particularołowe spectra.

Astronomers measured the locations and sizes of dark lines in spectra to calculate the amount of each element in a star’s spectrum. – Each chemical element leaves a unique pattern ofor dark bands of a certain wavelength in these spectra. It’s something like the fingerprints ofow – explained Professor Daniel Zucker of Macquarie University and the Australian Astronomical Observatory (AAO).

The accumulation of sufficient photonoin order to moc It takes about an hour to determine the chemical composition of a gyrase. – Fortunately, we can observe 360 stars simultaneously – emphasized Jeffrey Simpson of the AAO.

Measuring the abundance of each chemical in so many stars is a huge challenge. To do so, the compositeoGALAH has developed advanced analysis techniques. – We are training our computer code, The Cannon, to recognize patterns in the subset spectraoin the stars, whichore we analyzed. Then, through the use of algorithmsoin machine learning The Cannon determines the amounts of each element for all 340,000 stars – said Sven Burden of the Max Planck Institute in Germany. The code was named after Annie Jump Cannon, an American astronomer who lived 100 years ago, whoora has classified the spectra of about 340,000 stars.