Tag Archives: stars

Playing detective on a galactic scale: huge new dataset will solve multiple Milky Way mysteries

Australian-led GALAH project releases chemical information for 600,000 stars.

How do stars destroy lithium? Was a drastic change in the shape of the Milky Way caused by the sudden arrival of millions of stellar stowaways?

Day and night at the Anglo Australian Telescope. Half right image taken in the late afternoon, the Moon is up. Half left image taken just some few minutes before the beginning of the morning twilight of the same night. Orion and the Pleiades shine over the AAT on a very dark night. 4-5 November 2011. Siding Spring Observatory, NSW, Australia. Credit: Dr Ángel R. López-Sánchez/Australian Astronomical Optics/Macquarie University/ASTRO 3D

These are just a couple of the astronomical questions likely to be answered following the release today of ‘GALAH DR3’, the largest set of stellar chemical data ever compiled.

The data, comprising more than 500 GB of information gleaned from more than 30 million individual measurements, was gathered by astronomers including Sven Buder, Sarah Martell and Sanjib Sharma from Australia’s ARC Centre of Excellence in All Sky Astrophysics in 3 Dimensions (ASTRO 3D) using the Anglo Australian Telescope (AAT) at the Australian Astronomical Observatory at Siding Spring in rural New South Wales.

Continue reading Playing detective on a galactic scale: huge new dataset will solve multiple Milky Way mysteries

The short lives of hard-living, fast burning, high mass stars

2015 L'Oréal-UNESCO For Women in Science Fellow Shari Breen (Credit: L'Oréal Australia)Dr Shari Breen, astronomer, CSIRO, Sydney

We are made of star stuff. The nitrogen in our DNA, the calcium in our teeth and the iron in our blood were all made in high mass stars that burnt briefly and brightly before exploding.

Dr Shari Breen is using ‘The Dish’ at Parkes and a network of international telescopes to understand the life cycle and evolution of these stars. For her the 1,000 tonne Parkes radio telescope is an old friend that creaks and grumbles as she guides it across the sky, hunting for high mass stars.

She will use her L’Oréal-UNESCO For Women in Science Fellowship to develop her use of masers (laser-like beams of intense radio waves) to investigate these stars.

Continue reading The short lives of hard-living, fast burning, high mass stars

Galactic shutterbug

A new instrument at the Australian Astronomical Observatory (AAO) can sample the light coming from hundreds of galaxies per night—which can tell us new things about the universe.

Astronomer Sam Richards sitting in the prime focus cage at the Anglo-Australian Telescope, where the SAMI instrument usually sits. Credit: Jon Lawrence
Astronomer Sam Richards sitting in the prime focus cage at the Anglo-Australian Telescope, where the SAMI instrument usually sits. Credit: Jon Lawrence

Sydney-AAO Multi-object Integral field spectrograph (SAMI) can look at up to 100 galaxies in a night, because it can look at 60 different regions in each of 13 different galaxies, all at once.

But most observatories around the world can only do one galaxy at a time.
Continue reading Galactic shutterbug

Supercomputers bring theory to life

A DEPICTION OF THE DISTRIBUTION OF MATTER IN AN OBJECT NEARLY TEN MILLION LIGHT YEARS ACROSS AND A THOUSAND TIMES THE MASS OF THE MILKY WAY. THOUSANDS OF THESE EXIST IN THE OBSERVABLE UNIVERSE. CREDIT: GREG POOLE, SWINBURNE UNIVERSITY OF TECHNOLOGY.
A DEPICTION OF THE DISTRIBUTION OF MATTER IN AN OBJECT NEARLY TEN MILLION LIGHT YEARS ACROSS AND A THOUSAND TIMES THE MASS OF THE MILKY WAY. THOUSANDS OF THESE EXIST IN THE OBSERVABLE UNIVERSE. CREDIT: GREG POOLE, SWINBURNE UNIVERSITY OF TECHNOLOGY.

Over aeons of time cosmic gas comes together, stars begin to form, supernovae explode, galaxies collide. And computational astronomers can watch it all unfold inside a supercomputer. That’s the kind of work post-doctoral fellows Rob Crain and Greg Poole are doing at the Swinburne Centre for Astrophysics and Supercomputing. Continue reading Supercomputers bring theory to life

Mega star nursery gives birth to new knowledge

THE MASSIVE DENSE CLOUD OF HYDROGEN (SHOWN BY THE RED CONTOURS), CALLED BYF73, APPEARS TO BE COLLAPSING IN ON ITSELF DUE TO GRAVITY, FORMING HUGE PROTOSTARS (SEEN AS RED)
THE MASSIVE DENSE CLOUD OF HYDROGEN (SHOWN BY THE RED CONTOURS), CALLED BYF73, APPEARS TO BE COLLAPSING IN ON ITSELF DUE TO GRAVITY, FORMING HUGE PROTOSTARS (SEEN AS RED)

Enormous collapsing clouds of cosmic gas and dust may yield clues on how massive stars form, which is an enduring mystery of astronomy.

One such cloud, called BYF73, has been studied by a research team using CSIRO’s Mopra radio telescope. Peter Barnes, an Australian researcher working at the University of Florida in the US, leads the team. The massive hydrogen cloud is collapsing in on itself and will probably form a huge cluster of young stars. Continue reading Mega star nursery gives birth to new knowledge

Stellar immigration

DUNCAN FORBES IS IDENTIFYING ALIEN STARS. CREDIT: PAUL JONES.

If the Milky Way did grow by swallowing up smaller galaxies, then another team suspects it knows where in the Milky Way some of those alien stars are hiding.

Duncan Forbes of Swinburne University of Technology and his Canadian colleague Terry Bridges are using Hubble Space Telescope data to identify clusters of alien stars, using the fact that their age and chemical composition differs from their neighbours.

Continue reading Stellar immigration

Profiling and fingerprinting the stars

This story continues from Galactic archaeology— digging into the Milky Way’s past

RAVE PROJECT MANAGER, FRED WATSON, WITH THE UK SCHMIDT TELESCOPE. CREDIT: SHAUN AMY.
RAVE PROJECT MANAGER, FRED WATSON, WITH THE UK SCHMIDT TELESCOPE. CREDIT: SHAUN AMY.

But already, another Australian-led innovation in astronomical instrumentation is providing researchers with the critical information they need to understand the motions of stars within different parts of our galaxy, such as its main body, the bulging core, and the extended halo that surrounds it. Researchers are also searching for evidence of galactic cannibalism—swarms of stars that could be remnants of dwarf galaxies consumed by the Milky Way.

The innovation, called the 6dF instrument, is being used by a multinational consortium, the RAdial Velocity Experiment (RAVE), to measure the radial velocities of more than half a million stars. It is mounted on the Australian National University’s UK Schmidt Telescope at Siding Spring in New South Wales. Radial velocity is movement toward or away from the observer along the light of sight, as distinct from motion across the line of sight. The survey, which began in 2003, will be completed in 2011. Continue reading Profiling and fingerprinting the stars

Galactic archaeology— digging into the Milky Way’s past

ASTRONOMERS ARE HUNTING ‘FOSSIL’ STARS FROM GALAXIES DEVOURED BY THE MILKY WAY CREDIT: HUBBLE HERITAGE TEAM (AURA/STSCI/NASA/ESA)
ASTRONOMERS ARE HUNTING ‘FOSSIL’ STARS FROM GALAXIES DEVOURED BY THE MILKY WAY CREDIT: HUBBLE HERITAGE TEAM (AURA/STSCI/NASA/ESA)

Ken Freeman is hunting for fossils. But he’s not looking for old bones—he’s exploring the very origin and history of our Milky Way galaxy.

Conventional theory says that our galaxy grew big by engulfing smaller ones. If this is correct, stars from the original galaxies should be still identifiable within the main mass of stars via several tell-tale signs, from unusual velocities to spectral types. These stellar fossils would point to the galaxy’s birth and growth. Continue reading Galactic archaeology— digging into the Milky Way’s past

The destruction of a star

THE ZADKO TELESCOPE MAKING OBSERVATIONS NEAR GINGIN, 70 KILOMETRES NORTH OF PERTH. CREDIT: JOHN GOLDSMITH/CELESTIAL VISIONS.
THE ZADKO TELESCOPE MAKING OBSERVATIONS NEAR GINGIN, 70 KILOMETRES NORTH OF PERTH. CREDIT: JOHN GOLDSMITH/CELESTIAL VISIONS.

You have to be well prepared, quick and lucky to take a picture of an explosion, especially if that explosion occurred 11 billion years ago in a remote part of the Universe. Having the right equipment, plus friends in high places, certainly helps. And that’s exactly what the Zadko Telescope—managed by the University of Western Australia at the Gingin Observatory about 70 kilometres north of Perth—does have.

In December 2008, just after it was installed, the telescope was first on the scene to record for future analysis the afterglow of a momentous event—a huge explosion as a star collapsed into a black hole releasing a massive gamma-ray burst. It’s the kind of happening the one-metre Zadko Telescope, currently the largest optical telescope in Western Australia, was built to observe. And it performed flawlessly, outpacing the world’s most powerful telescopes at the European Southern Observatory in Chile.

Continue reading The destruction of a star

Is the Red Rectangle a cosmic Rosetta Stone?

THE RED RECTANGLE IS A PECULIAR NEBULA WITH SOME STRANGE CHEMICAL PROPERTIES. CREDIT: NASA/ESA/ HANS VAN WINCKEL (CATHOLIC UNIVERSITY OF LEUVEN) /MARTIN COHEN (UCB).
THE RED RECTANGLE IS A PECULIAR NEBULA WITH SOME STRANGE CHEMICAL PROPERTIES. CREDIT: NASA/ESA/ HANS VAN WINCKEL (CATHOLIC UNIVERSITY OF LEUVEN) /MARTIN COHEN (UCB).

Cracking the puzzle of unusual molecules in deep space that absorb some wavelengths of starlight is like unlocking the secrets of the Rosetta Stone, according to Rob Sharp of the Australian National University’s Research School of Astronomy and Astrophysics. “It’s the longest-standing problem in astronomical spectroscopy,” he says.

The identity of the molecules has been a mystery for 80 years, but Rob has now joined forces with chemists at the University of Sydney to try to crack the molecular code. Continue reading Is the Red Rectangle a cosmic Rosetta Stone?