340,000 stars’ DNA checked for finding the Lost Siblings of Sun

340,000 stars’ DNA checked for finding the Lost Siblings of Sun

This NASA/ESA Hubble Space Telescope image shows the globular cluster NGC 1854, a gathering of white and blue stars in the southern constellation of Dorado (The Dolphinfish). NGC 1854 is located about 135 000 light-years away, in the Large Magellanic Cloud (LMC), one of our closest cosmic neighbours and a satellite galaxy of the Milky Way. The LMC is a hotbed of vigorous star formation. Rich in interstellar gas and dust, the galaxy is home to approximately 60 globular clusters and 700 open clusters. These clusters are frequently the subject of astronomical research, as the Large Magellanic Cloud and its little sister, the Small Magellanic Cloud, are the only systems known to contain clusters at all stages of evolution. Hubble is often used to study these clusters as its extremely high-resolution cameras can resolve individual stars, even at the clusters’ crowded cores, revealing their mass, size and degree of evolution.

“The GALAH team’s aim is to make DNA matches between stars to find their long-lost sisters and brothers.” Dr. Sarah Martell said.

The curiosity of humans to know more and more about the universe is the root cause of all the technological advancements we observe in this era. Scientists are discovering the far-off areas of space in search of amazing facts. Similarly, latest techniques are being used to analyze the underwater life as deep sea missions are arranged.

According to the latest announcement, a team of astronomers has collected the DNA of more than 340,000 stars scattered throughout our galaxy in order to locate the siblings of our Sun. A DNA of anything holds all the historical information about it and that’s why researchers are hopeful that they will succeed in their plans.

The formulation and evolution of galaxies is a massive question which still needs scientific explanation despite the Big Bang Theory. A Galactic Archaeology survey, called GALAH, was launched in 2013 with the aim of investigating a million stars. It is a collective effort from the scientists of University of New South Wales in Australia and European researchers. 3.9-meter Anglo-Australian Telescope was used at the Australian Astronomical Observatory (AAO) to gather data of these stars through HERMES spectrograph.

The researching team is quite hopeful that this discovery will explain how the universe evolved with time as all that we have today began with just Hydrogen and Helium. Nearly 1.6 billion stars were mapped for this experiment which made it, by far, the biggest and most accurate atlas of the night sky. Dr. Gayandhi De Silva, who led the experiment, was delighted as she told the world about it in the following words:

No other survey has been able to measure as many elements for as many stars as GALAH. This data will enable such discoveries as the original star clusters of the Galaxy, including the Sun’s birth cluster and solar siblings — there is no other dataset like this ever collected anywhere else in the world.”

The process of collecting DNA of stars becomes much more difficult because all of those born in the same cluster share the same chemical elements like Oxygen and Iron. The only difference between their DNA is the composition of these elements. As a result, a special method, called Spectroscopy, is needed to collect them.

The light of each star is gathered by making use of a telescope. It is then passed through a spectrograph which is responsible for distributing it into its constituent colors. The location and size of each of these lines are then observed by the experts to figure the exact amount of each element in a star. Daniel Zucker, an Associate Professor at AAO, explained that as he said,

Each chemical element leaves a unique pattern of dark bands at specific wavelengths in these spectra, like fingerprints.”

The team spent 280 nights at the telescope to gather this precious data as the examination of a single star can take considerable duration. Luckily, optical fibers give them the leverage to analyze 360 stars simultaneously. Given the scale of the job, GALAH had to look for sophisticated techniques as measuring the quantity of each element in so many stars is nearly impossible. Sven Buder, the Lead Author of the Scientific Article which explained this data release, explained their advanced investigation method in the following words.

We train [our computer code] The Cannon to recognize patterns in the spectra of a subset of stars that we have analyzed very carefully, and then use The Cannon’s machine learning algorithms to determine the amount of each element for all of the 340,000 stars.”  

The name of this system came from an American astronomer, Annie Jump Cannon. She examined a spectrum of 340,000 stars by eye some hundred years ago. It took her several decades to accomplish this feat. According to a representative of GALAH, the system they have developed can analyze this many stars in less than a day with a lot of detailed examination.

European Gaia satellite released massive data of 1.6 billion stars on 25th April that gives us the motion of these stars in addition to the distances and positions. A lot of scientists are appreciating this study as they hope that it will provide humans with a detailed understanding of the Milky Way.

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