Institute of Astronomy

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I smelled comet 67P’s deadly pong and lived to tell the tale

Astronomy News - 24 June 2016 - 8:58am

Researchers with ESA's Rosetta mission have commissioned a perfume that mimics the odour of 67P/Churyumov–Gerasimenko. Jacob Aron shares his first sniff

Hubble spots a new long-lived storm raging on Neptune

Astronomy News - 24 June 2016 - 8:56am

Neptune is known for its Great Dark Spot, but a new blemish appeared last summer and has been roiling ever since

LIGO detects whispers of another black-hole merger

Astronomy News - 23 June 2016 - 9:23am

LIGO detects whispers of another black-hole merger

Nature 534, 7608 (2016). http://www.nature.com/doifinder/10.1038/nature.2016.20093

Author: Davide Castelvecchi

After historic first discovery last September, twin observatories detected gravitational waves again on Boxing Day.

The first gravitational-wave source from the isolated evolution of two stars in the 40–100 solar mass range

Astronomy News - 23 June 2016 - 9:22am

The first gravitational-wave source from the isolated evolution of two stars in the 40–100 solar mass range

Nature 534, 7608 (2016). doi:10.1038/nature18322

Authors: Krzysztof Belczynski, Daniel E. Holz, Tomasz Bulik & Richard O’Shaughnessy

The merger of two massive (about 30 solar masses) black holes has been detected in gravitational waves. This discovery validates recent predictions that massive binary black holes would constitute the first detection. Previous calculations, however, have not sampled the relevant binary-black-hole progenitors—massive, low-metallicity binary stars—with sufficient accuracy nor included sufficiently realistic physics to enable robust predictions to better than several orders of magnitude. Here we report high-precision numerical simulations of the formation of binary black holes via the evolution of isolated binary stars, providing a framework within which to interpret the first gravitational-wave source, GW150914, and to predict the properties of subsequent binary-black-hole gravitational-wave events. Our models imply that these events form in an environment in which the metallicity is less than ten per cent of solar metallicity, and involve stars with initial masses of 40–100 solar masses that interact through mass transfer and a common-envelope phase. These progenitor stars probably formed either about 2 billion years or, with a smaller probability, 11 billion years after the Big Bang. Most binary black holes form without supernova explosions, and their spins are nearly unchanged since birth, but do not have to be parallel. The classical field formation of binary black holes we propose, with low natal kicks (the velocity of the black hole at birth) and restricted common-envelope evolution, produces approximately 40 times more binary-black-holes mergers than do dynamical formation channels involving globular clusters; our predicted detection rate of these mergers is comparable to that from homogeneous evolution channels. Our calculations predict detections of about 1,000 black-hole mergers per year with total masses of 20–80 solar masses once second-generation ground-based gravitational-wave observatories reach full sensitivity.

Astrophysics: Recipe for a black-hole merger

Astronomy News - 23 June 2016 - 9:21am

Astrophysics: Recipe for a black-hole merger

Nature 534, 7608 (2016). doi:10.1038/534478a

Authors: J. J. Eldridge

The detection of a gravitational wave was a historic event that heralded a new phase of astronomy. A numerical model of the Universe now allows researchers to tell the story of the black-hole system that caused the wave. See Letter p.512

Giant SKA telescope rattles South African community

Astronomy News - 23 June 2016 - 9:21am

Giant SKA telescope rattles South African community

Nature 534, 7608 (2016). http://www.nature.com/doifinder/10.1038/534444a

Author: Sarah Wild

Struggle in Northern Cape province highlights a balancing act that scientists leading gigantic projects face.

Astronomy: Early galaxy has wisps of oxygen

Astronomy News - 23 June 2016 - 9:21am

Astronomy: Early galaxy has wisps of oxygen

Nature 534, 7608 (2016). doi:10.1038/534438c

Astronomers have detected oxygen in a 13-billion-year-old galaxy — the first time that the gas has been found at such an early stage of the Universe.A team led by Akio Inoue at Osaka Sangyo University in Daito, Japan, used the powerful Atacama Large Millimeter/submillimeter

Successful First Observations of Galactic Centre with GRAVITY

Astronomy News - 23 June 2016 - 9:15am
A European team of astronomers have used the new GRAVITY instrument at ESO’s Very Large Telescope to obtain exciting observations of the centre of the Milky Way by combining light from all four of the 8.2-metre Unit Telescopes for the first time. These results provide a taste of the groundbreaking science that GRAVITY will produce as it probes the extremely strong gravitational fields close to the central supermassive black hole and tests Einstein’s general relativity.

Pluto must have liquid ocean or it’d look like an overripe peach

Astronomy News - 23 June 2016 - 9:08am

If Pluto’s inner sea froze recently, we should see ridges popping up in the dwarf planet's outer shell. Since we don’t, it's probably still liquid

LIGO black hole pair may be stars that lived and died together

Astronomy News - 23 June 2016 - 9:07am

We’ve now seen enough gravitation waves to start wondering about the formation of the binary black holes that cause the signals when they spiral in and collide

Find exomoons by watching how they warp their planet’s light

Astronomy News - 22 June 2016 - 8:47am

A new way of detecting exomoons circling young giant planets could be possible with the next generation of telescopes

Asteroids keep their rings safe from gas giants’ clutches

Astronomy News - 22 June 2016 - 8:46am

If an asteroid acquires rings, it’s likely to hang on to them – so more space rocks may have rings than we thought. If only we knew how they got there

Venus has potential – but not for water

Astronomy News - 21 June 2016 - 9:26am

ESA's Venus Express may have helped to explain the puzzling lack of water on Venus. The planet has a surprisingly strong electric field – the first time this has been measured at any planet – that is sufficient to deplete its upper atmosphere of oxygen, one of the components of water.

The alien world that’s being vaporised by a death ray

Astronomy News - 21 June 2016 - 9:25am

A Mercury-sized exoplanet is being blown apart like a dandelion – and magnetic hotspots on its star could make things worse

Mars crater named after Nepal quake village Langtang

Astronomy News - 20 June 2016 - 9:30am

A crater on Mars is named Langtang, in tribute to one of the worst-hit villages during the 2015 Nepal earthquake.

Nearly naked black hole lost its ‘clothes’ to a gravity rip tide

Astronomy News - 20 June 2016 - 9:29am

Supermassive black holes are meant to be swaddled inside the starry cloak of a galaxy, but astronomers have just seen one that's almost bare

ALMA Observes Most Distant Oxygen Ever

Astronomy News - 17 June 2016 - 11:31am
A team of astronomers has used the Atacama Large Millimeter/submillimeter Array (ALMA) to detect glowing oxygen in a distant galaxy seen just 700 million years after the Big Bang. This is the most distant galaxy in which oxygen has ever been unambiguously detected, and it is most likely being ionised by powerful radiation from young giant stars. This galaxy could be an example of one type of source responsible for cosmic reionisation in the early history of the Universe.

Unexpected Excess of Giant Planets in Star Cluster

Astronomy News - 17 June 2016 - 11:30am
An international team of astronomers have found that there are far more planets of the hot Jupiter type than expected in a cluster of stars called Messier 67. This surprising result was obtained using a number of telescopes and instruments, among them the HARPS spectrograph at ESO’s La Silla Observatory in Chile. The denser environment in a cluster will cause more frequent interactions between planets and nearby stars, which may explain the excess of hot Jupiters.

Is NASA doing enough to look for alien life?

Astronomy News - 17 June 2016 - 11:29am

A new study says Hubble's successor could spot alien life on three new exoplanets. Should NASA be doing more? Or is it right to focus on other priorities?

LIGO discovers new gravitational wave – and new era of astronomy

Astronomy News - 17 June 2016 - 11:29am

The detector's latest discovery means we are now firmly in a new era of astronomy – it matches up convingingly with what we already know about black holes