Ancient star helps scientists understand universe's origins

[Buster's Uncle]

Ancient star helps scientists understand universe's origins
Reuters  February 9, 2014 11:16 PM



SYDNEY (Reuters) - Australian astronomers have found the oldest known star in the universe, a discovery that may help to resolve a long-standing discrepancy between observations and predictions of the Big Bang billions of years ago.

Dr Stefan Keller, lead researcher at the Australian National University Research School, told Reuters his team had seen the chemical fingerprint of the "first star". After 11 years of searching, the star was discovered using the SkyMapper telescope at the Siding Spring Observatory.

"This star was formed shortly after the Big Bang 13.7 billion years ago," Keller said.

"It's giving us insight into our fundamental place in the universe. What we're seeing is the origin of where all the material around us that we need to survive came from."

Simply put, the Big Bang was the inception of the universe, he said, with nothing before that event.

The ancient star is about 6,000 light years from Earth - relatively close in astronomical terms. It was one of 60 million stars photographed by SkyMapper in its first year.

"This is the first time we've unambiguously been able to say we've got material from the first generation of stars," Keller said. "We're now going to be able to put that piece of the jigsaw puzzle in its right place."

The composition of the newly discovered star shows it formed in the wake of a primordial star, which had a mass 60 times that of our Sun.

Keller said it was previously thought primordial stars died in extremely violent explosions that polluted huge volumes of space with iron. But the ancient star shows signs of pollution with lighter elements such as carbon and magnesium - with no sign of iron.

"What that means is we had a long-held theory that the first stars to form would be extremely massive because they are formed out of pure hydrogen and helium," he said.

"A star is like an onion - it has all these layers and the heaviest material like iron is right down in the core. The only thing to come out of it was the carbon and a little bit of magnesium from that supernova and that's what we're seeing today in the star that we've discovered."

The discovery was published in the latest edition of the journal Nature.


http://news.yahoo.com/ancient-star-helps-scientists-understand-universe-39-origins-041628818.html

[Buster's Uncle]

Ancient Star May Be Oldest in Known Universe
SPACE.com
by Miriam Kramer, Staff Writer  12 hours ago



Astronomer Stefen Keller is shown working in the SkyMapper Telescope at the Australian National University's Siding Spring Observatory. Keller led a study at the observatory that discovered SMSS J031300.362670839.3



Astronomers have found what appears to be one of the oldest known stars in the universe.

The ancient star formed not long after the Big Bang 13.8 billion years ago, according to Australia National University scientists. The star (called SMSS J031300.362670839.3) is located 6,000 light-years from Earth and formed from the remains of a primordial star that was 60 times more massive than the sun.

"This is the first time that we've been able to unambiguously say that we've found the chemical fingerprint of a first star," lead scientist Stefan Keller, of the ANU Research School of Astronomy and Astrophysics, said in a statement. "This is one of the first steps in understanding what those first stars were like. What this star has enabled us to do is record the fingerprint of those first stars."

Scientists think SMSS J031300.362670839.3 is probably at least 13 billion years old, though they do not know its exact age, Anna Frebel, an MIT astronomer associated with the research, said

Keller and his team found that the star actually has an unexpected composition. Astronomers thought that primordial stars — like the one that SMSS J031300.362670839.3 formed from — died in huge supernova explosions that spread large amounts of iron throughout space.

However, the new observations have shown that SMSS J031300.362670839.3's composition harbors no iron pollution. Instead, the star is mostly polluted by lighter elements like carbon, ANU officials said.

"This indicates the primordial star's supernova explosion was of surprisingly low energy," Keller said. "Although sufficient to disintegrate the primordial star, almost all of the heavy elements such as iron, were consumed by a black hole that formed at the heart of the explosion."

The scientists also found that the early star's composition is very different from the sun.

"To make a star like our sun, you take the basic ingredients of hydrogen and helium from the Big Bang and add an enormous amount of iron — the equivalent of about 1,000 times the Earth's mass," Keller said. "To make this ancient star, you need no more than an Australia-sized asteroid of iron and lots of carbon. It's a very different recipe that tells us a lot about the nature of the first stars and how they died."

Because of its low mass, the star, located in the Milky Way, has a long lifetime, Anna Frebel, an MIT astronomer associated with the research, told Space.com via email.

Keller and his team found SMSS J031300.362670839.3 by using the ANU SkyMapper telescope. SkyMapper is surveying the sky at the Siding Spring Observatory in Australia to produce the first-ever digital map of the sky in the Southern Hemisphere. They confirmed their observations using the Magellan telescope in Chile.

The new results are detailed in the journal Nature.


http://news.yahoo.com/ancient-star-may-oldest-known-universe-143549926.html