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Oldest known star in the Universe discovered


February 10, 2014

The ANU SkyMapper telescope at the Siding Spring Observatory has discovered the oldest known star in the Universe (Photo: ANU)

The ANU SkyMapper telescope at the Siding Spring Observatory has discovered the oldest known star in the Universe (Photo: ANU)

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A team of astronomers at The Australian National University (ANU) working on a five-year project to produce the first comprehensive digital survey of the southern sky has discovered the oldest known star in the Universe. Just a 6,000 light year astronomical hop, skip and jump from Earth, the ancient star formed shortly after the Big Bang 13.7 billion years ago.

Similar to the Sloan Digital Sky Survey (SDSS), which is mapping the Northern Hemisphere sky, the SkyMapper Southern Sky Survey is casting its telescopic eye on the southern sky. In the first year of the five-year project, the ANU SkyMapper telescope at the Siding Spring Observatory about 500 km (310 miles) north west of Sydney has photographed some 60 million stars.

As well as creating a comprehensive census of the stars in the southern sky, SkyMapper is also tasked with mapping dark matter and uncovering the first quasars and stars to form after the birth of the Universe. The SkyMapper telescope is able to find such ancient stars through its ability to detect, through their color, stars with low iron.

"The stars we are finding number one in a million," said team member Professor Mike Bessell, who worked with Dr Stefan Keller of the ANU Research School of Astronomy and Astrophysics on the research.

The researchers say the discovery will provide a better idea of what the Universe was like in its infancy by allowing the study of the chemistry of the first stars. According to the team, 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.

"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,” said Dr Keller. "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."

Although it was previously believed that the death of primordial stars involved extremely violent explosions that spread iron over huge volumes of space, the ancient star shows signs of lighter elements, such as carbon and magnesium, but no sign of iron.

"This indicates the primordial star’s supernova explosion was of surprisingly low energy," said Dr Keller. "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 ancient star's discovery was confirmed using the Magellan telescope in Chile, and a paper detailing the discovery is published in the journal Nature. Data collected by the survey, which is funded by the Australia Research Council, will also be made freely available on the internet.

Source: Australian National University

About the Author
Darren Quick Darren's love of technology started in primary school with a Nintendo Game & Watch Donkey Kong (still functioning) and a Commodore VIC 20 computer (not still functioning). In high school he upgraded to a 286 PC, and he's been following Moore's law ever since. This love of technology continued through a number of university courses and crappy jobs until 2008, when his interests found a home at Gizmag. All articles by Darren Quick

"Shortly" after the Big Bang? How shortly? Red giant HE 1523-0901 is thought to be 13.2 billion years old. It, too, is a second generation star. That doesn't leave much room for anything to be older in our 13.7 Byo universe. This should be taken in the context of the rather high uncertainty of measuring the age of old stars: 0.7 to 2.7 billion years according to wikipedia.

What we have here is astronomers hungry for press.


How can an individual star be resolved that far away? How do you know its distance and not gravitational red shifting?

Gene Preston

I agree that probability of error in determining may be very high, yet, a question comes to my mind; in the direction of the star (and as is thought to be time-wise closer to Big Bang), I am lured to think that we are looking into the surroundings where Big Bang might possibly have taken place. Its 3-D location would then be close to our own galaxy! Now the probability of having this outcome is very very low. I wish Darren would gather data on that aspect and let us have more on the aging as well location of the star, if possible. Regards.


Where can I order a "billion year" calender? How much do they cost? When did they started that calender and did they use the sun and earth to keep time or did they use time from a far off place? I would also like to know the day and month - not just a rounded off number.


Gene. Resolve the star? If they can't then they don't have the information to calculate from and they'll be beaten with soap in socks at the next Aussie Astronomers Get Together (AAGT, it's awesome I hear) Gravitational redshifting? More important than the others? Anywho, get your redshifted light, throw it at a prism then look at the spectrum and "shift" it until it makes sense for an emission from XYZ particles.

All in all, I didn't know there were 2nd gen stars still around, that's awesome!

Craig Jennings

hmm .. 6000 light yrs away ? That's inside our galaxy. How does that work ? Are we in one of the oldest galaxies in the universe or ??


my mistake - looking for an article on Judi Dench..

Brian Snider
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