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Home https://server7.kproxy.com/servlet/redirect.srv/sruj/smyrwpoii/p2/ Science https://server7.kproxy.com/servlet/redirect.srv/sruj/smyrwpoii/p2/ Oldest Known Stars in the Galaxy Found in the Milky Way's Bulge

Oldest Known Stars in the Galaxy Found in the Milky Way's Bulge



 New research shows that the star cluster HP1 (seen here through Chile's Gemini South telescope) may contain some of the oldest stars in the Milky Way, dating to roughly 12.8 billion years old. </p>
<p>                    <cite class= Credit: Gemini Observatory / AURA / NSF; composite image produced by Mattia Libralato of the Space Telescope Science Institute

Astronomers peered into the dusky bulge of the Milky Way and found some of the oldest known stars in the universe

In a study to be published in the April 201

9 issue of the journal Astronomical Society, researchers analyzed a cluster of old, dim stars called HP1, located about 21,500 light-years away from Earth in the gut of our central gully. Using observations from Chile's Gemini South telescope and archival Hubble Space Telescope data, researchers have estimated the age of the stars to be roughly 12.8 billion years old – making them some of the oldest stars ever detected in either the Milky Way or the universe at large.

"These are also some of the oldest stars we've seen anywhere," study co-author Stefano Souza, a doctoral candidate at the University of Sao Paulo, Brazil, said in a statement. [15 Unforgettable Images of Stars]

The Milky Way's bulge – a bulbous, 10,000 light-year-wide region of stars and dust popping out of the galaxy's spiral disc – is thought to contain some of the oldest stars in the galaxy. studies have tried to prove that ancient stars were hiding in the Milky Way's bulge by studying HP1 and other nearby clusters. But Souza and his colleagues analyzed the problem with unprecedented resolution, thanks to an imaging technique called adaptive optics – essentially, a method that corrects pictures of space for light distortions caused by Earth's atmosphere

By combining these ultra-high definition observations and reviewing archival footage from Hubble, the team calculated the distance to Earth for even the dimmest, most dust-covered stars in HP1. These distances helped the team to calculate each star's brightness. The intensity and color of each star's light, in turn, reveals the star type – whether it was a dwarf or a giant, for example, or whether it emitted a lot of elements heavier than hydrogen and helium

The weight of a star's elements – also called its "metallicity" – are crucial information for scientists who study aging celestial bodies. Researchers suspect that the universe's earliest stars formed out of primordial clouds of pure hydrogen gas. The universe's first helium atoms are thought to have emerged from the nuclear reactions at the hearts of these ancient stars .. Eventually, as more and more stars were born, every other element now known to humans exploded into existence

Stars that produce a lot of elements heavier than hydrogen and helium are therefore considered to be relatively young in the cosmic scheme of things. So, when the Gemini researchers saw that the stars of HP1 were extremely light on heavy elements, they knew they had an old cluster in their sight.

The team calculated that stars are likely to date in the first billion years of the universe's life

"HP 1 is one of the surviving members of the fundamental building blocks that assembled our galaxy's inner bulge," lead study author Leandro Kerber of the University of Sao Paulo and Brazil's State University of

The fact that the Milky Way hides ancient stars in its bulging midsection means the area is the perfect location for studying our galaxy's awkward childhood years

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