Institute of Astronomy

Astronomy News

First global Mercury map shows its hills and valleys in detail

10 May 2016 - 9:31am

The team behind NASA's Messenger mission to Mercury has released the first global topographic map of the planet – just in time for its biggest show of the decade

Stars burn away the atmospheres of close-in super-Earths

9 May 2016 - 9:07am

We haven’t seen any super-Earth orbiting close to their host stars because the stars have shredded the planets’ atmospheres, making them look smaller

Mercury completes journey across Sun

9 May 2016 - 9:05am

The Solar System's smallest planet has made one of its irregular passes between the Earth and Sun.

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