Institute of Astronomy

Astronomy News

Was gravitational wave signal from a gravastar, not black holes?

6 May 2016 - 9:18am

LIGO’s discovery of gravitational waves was a great achievement, but a new analysis suggests the signal could have come from a rather exotic source

How to watch Mercury pass in front of the sun next Monday

6 May 2016 - 9:17am

You'll need special telescopes to watch the innermost planet transit the sun, an event lasting around seven hours, or you can watch online

Resolved atomic lines reveal outflows in two ultraluminous X-ray sources

5 May 2016 - 9:45am

Resolved atomic lines reveal outflows in two ultraluminous X-ray sources

Nature 533, 7601 (2016). doi:10.1038/nature17417

Authors: Ciro Pinto, Matthew J. Middleton & Andrew C. Fabian

Ultraluminous X-ray sources are extragalactic, off-nucleus, point sources in galaxies, and have X-ray luminosities in excess of 3 × 1039 ergs per second. They are thought to be powered by accretion onto a compact object. Possible explanations include accretion onto neutron stars with strong magnetic fields, onto stellar-mass black holes (of up to 20 solar masses) at or in excess of the classical Eddington limit, or onto intermediate-mass black holes (103–105 solar masses). The lack of sufficient energy resolution in previous analyses has prevented an unambiguous identification of any emission or absorption lines in the X-ray band, thereby precluding a detailed analysis of the accretion flow. Here we report the presence of X-ray emission lines arising from highly ionized iron, oxygen and neon with a cumulative significance in excess of five standard deviations, together with blueshifted (about 0.2 times light velocity) absorption lines of similar significance, in the high-resolution X-ray spectra of the ultraluminous X-ray sources NGC 1313 X-1 and NGC 5408 X-1. The blueshifted absorption lines must occur in a fast-outflowing gas, whereas the emission lines originate in slow-moving gas around the source. We conclude that the compact object in each source is surrounded by powerful winds with an outflow velocity of about 0.2 times that of light, as predicted by models of accreting supermassive black holes and hyper-accreting stellar-mass black holes.

Software error doomed Japanese Hitomi spacecraft

5 May 2016 - 9:45am

Software error doomed Japanese Hitomi spacecraft

Nature 533, 7601 (2016). http://www.nature.com/doifinder/10.1038/nature.2016.19835

Author: Alexandra Witze

Space agency declares the astronomy satellite a loss.

US and China eye up European gravitational-wave mission

5 May 2016 - 9:43am

US and China eye up European gravitational-wave mission

Nature 533, 7601 (2016). http://www.nature.com/doifinder/10.1038/533019a

Author: Elizabeth Gibney

Space-based detector draws interest, but regulatory hurdles might complicate a partnership.

Planetary science: Martian water on the boil

5 May 2016 - 9:42am

Planetary science: Martian water on the boil

Nature 533, 7601 (2016). doi:10.1038/533011b

Water boiling under Mars's thin atmosphere could explain some of the planet's puzzling geological features, such as gullies (pictured) and hillside streaks, which some scientists have attributed to liquid water flowing today.A team led by Marion Massé of the University of Nantes

Unexplained plume over Mars could be caused by solar outburst

5 May 2016 - 9:39am

Planetary scientists are struggling to figure out how a massive cloud appeared high above Mars in 2012, but now they may have an answer  

New exoplanet trio may have been dried out by fiery young star

5 May 2016 - 9:38am

Three recently discovered nearby exoplanets may not be as habitable as they first looked, as their hot young star could have left them high and dry

The 2016 Transit of Mercury

4 May 2016 - 9:28am

On May 9, 2016, they will see a strange spot on the sun--a dark circle moving across the solar disk. This is no ordinary sunspot. It's the planet Mercury, making a rare transit of the sun.

Unique Fragment from Earth’s Formation Returns after Billions of Years in Cold Storage

3 May 2016 - 9:40am
Astronomers have found a unique object that appears to be made of inner Solar System material from the time of Earth’s formation, which has been preserved in the Oort Cloud far from the Sun for billions of years. Observations with ESO’s Very Large Telescope, and the Canada France Hawai`i Telescope, show that C/2014 S3 (PANSTARRS) is the first object to be discovered on a long-period cometary orbit that has the characteristics of a pristine inner Solar System asteroid. It may provide important clues about how the Solar System formed.

Japanese satellite’s death spiral linked to software malfunction

3 May 2016 - 9:39am

The Hitomi X-ray space telescope has failed just months after its launch, leaving astronomers hoping to glimpse black holes devastated

Strange Manx comet is time capsule from the early solar system

3 May 2016 - 9:38am

The tiny-tailed comet C/2014 S3 is a preserved piece of the original material that made the rocky planets, not a dirty snowball like its cometary siblings

Trio of Earth-sized planets around nearby star could reveal life

3 May 2016 - 9:36am

Astronomers have discovered three exoplanets in orbit around a nearby dwarf star, making them good targets for atmospheric analysis