Tag Archives: astronomy

Orbits of ancient stars prompt rethink on Milky Way evolution

Australian telescopes and European satellite combine to reveal unexpected motions among the Galaxy’s rarest objects

Theories on how the Milky Way formed are set to be rewritten following discoveries about the behaviour of some of its oldest stars.

An investigation into the orbits of the Galaxy’s metal-poor stars – assumed to be among the most ancient in existence – has found that some of them travel in previously unpredicted patterns.

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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.

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Elements of surprise: neutron stars contribute little, but something’s making gold, research finds

Colliding neutron stars were touted as the main source of some of the heaviest elements in the Periodic Table. Now, not so much

Neutron star collisions do not create the quantity of chemical elements previously assumed, a new analysis of galaxy evolution finds.

The research also reveals that current models can’t explain the amount of gold in the cosmos – creating an astronomical mystery.

The work has produced a new-look Periodic Table, showing the stellar origins of naturally occurring elements from carbon to uranium.

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Hungry galaxies grow fat on the flesh of their neighbours

Modelling shows big galaxies get bigger by merging with smaller ones

Distribution of dark matter density overlayed with the gas density. This image cleanly shows the gas channels connecting the central galaxy with its neighbours. Credit: Gupta et al/ASTRO 3D/ IllustrisTNG collaboration.

Galaxies grow large by eating their smaller neighbours, new research reveals.

Exactly how massive galaxies attain their size is poorly understood, not least because they swell over billions of years. But now a combination of observation and modelling from researchers led by Dr Anshu Gupta from Australia’s ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D) has provided a vital clue.

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Spin doctors: Astrophysicists find when galaxies rotate, size matters

Sky survey provides clues to how they change over time.

A simulation showing a section of the Universe at its broadest scale. A web of cosmic filaments forms a lattice of matter, enclosing vast voids. Credit: Tiamat simulation, Greg Poole

The direction in which a galaxy spins depends on its mass, researchers have found.

A team of astrophysicists analysed 1418 galaxies and found that small ones are likely to spin on a different axis to large ones. The rotation was measured in relation to each galaxy’s closest “cosmic filament” – the largest structures in the universe.

Filaments are massive thread-like formations, comprising huge amounts of matter – including galaxies, gas and, modelling implies, dark matter. They can be 500 million light years long but just 20 million light years wide. At their largest scale, the filaments divide the universe into a vast gravitationally linked lattice interspersed with enormous dark matter voids.

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The ‘coolest’ place for astronomy

High on the Antarctic Plateau, in one of the coldest places on Earth, a group of telescopes are peering through stellar dust clouds into the heart of our galaxy.

The cold helps counteract interference from the telescopes and surrounding equipment, which can hinder our ability to see relatively
‘cool’ objects in space, such as asteroids, young stars, and interstellar gas.

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Anaemic star carries the mark of its ancient ancestor

Australian-led astronomers find the most iron-poor star in the Galaxy, hinting at the nature of the first stars in the Universe.

A visualisation of the formation of the first stars. Credit: Wise, Abel, Kaehler (KIPAC/SLAC)

A newly discovered ancient star containing a record-low amount of iron carries evidence of a class of even older stars, long hypothesised but assumed to have vanished.

In a paper published in the journal Monthly Notices of the Royal Astronomical Society: Letters, researchers led by Dr Thomas Nordlander of the ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D) confirm the existence of an ultra-metal-poor red giant star, located in the halo of the Milky Way, on the other side of the Galaxy about 35,000 light-years from Earth.

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Astronomer flies high to spy on star formation

Dr Stuart Ryder is venturing into the stratosphere on a NASA jet to study the birthplace of massive stars.

Macquarie University astronomer Dr Stuart Ryder is in New Zealand to hitch a ride on a NASA jet and take a closer look at how stars are born in one of the most active stellar nurseries ever seen.

“We’re looking at a molecular cloud called BYF73, which is collapsing in on itself at extremely high speeds and forming massive stars,” says Stuart, who is an Adjunct Fellow with the Department of Physics and Astronomy at Macquarie University.

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The world’s largest scientific instrument

In a whisper-quiet area of the outback in Western Australia, 133,000 radio telescope antennas are about to be built.

When complete, they’ll be able to pick up radio signals from the time when the first stars in the universe formed.

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