Institute of Astronomy

Astronomy News

Galactic smash-ups turn on the lights around black holes

6 May 2015 - 10:47am
Trails of stellar debris suggest that ancient galactic crashes funnelled gas toward a central black hole, sparking active galaxies' inner glow

Microwave baffles space scientists

6 May 2015 - 10:46am

Australian scientists discover that mysterious signals hitting a renowned space telescope are actually from microwaves.

Fire and Ice: A MESSENGER Recap

5 May 2015 - 11:57am
NASA's MESSENGER spacecraft crashed into Mercury on April 30th, ending a years-long mission that made many unexpected discoveries about the innermost planet. Today's story summarizes some of MESSENGER's most surprising finds.

The Pillars of Creation Revealed in 3D

5 May 2015 - 11:56am
Using the MUSE instrument on ESO’s Very Large Telescope (VLT), astronomers have produced the first complete three-dimensional view of the famous Pillars of Creation in the Eagle Nebula, Messier 16. The new observations demonstrate how the different dusty pillars of this iconic object are distributed in space and reveal many new details — including a previously unseen jet from a young star. Intense radiation and stellar winds from the cluster’s brilliant stars have sculpted the dusty Pillars of Creation over time and should fully evaporate them in about three million years.

AKARI far-infrared all-sky data released

5 May 2015 - 11:54am

The AKARI space telescope's far-infrared all-sky image data are now available to researchers everywhere. The new all-sky maps have four to five times better spatial resolution than conventional far-infrared all-sky images, and include data at longer wavelengths.

The Presidents of the RAS and IoP welcome the decision to site the permanent hea...

5 May 2015 - 11:54am
The Presidents of the RAS and IoP welcome the decision to site the permanent headquarters of the Square Kilometre Array (SKA) project at Jodrell Bank in the UK.

The SKA will be the world's most powerful radio telescope, funded by 11 countries and expected to begin operations in 2020.

RAS and IOP Presidents: SKA HQ is great news for radio astronomy and UK science
The Presidents of the Royal Astronomical Society and the Institute of Physics have welcomed the decision to site the permanent headquarters of the Square Kilometre Array (SKA) in the UK.

NASA Completes MESSENGER Mission with Expected Impact on Mercury's Surface

5 May 2015 - 11:54am
A NASA planetary exploration mission came to a planned, but nonetheless dramatic, end Thursday when it slammed into Mercury’s surface at about 8,750 mph and created a new crater on the planet’s surface.

Astronomers find first evidence of changing conditions on a super Earth

5 May 2015 - 11:49am

For the first time, researchers led by the University of Cambridge have detected atmospheric variability on a rocky planet outside the solar system, and observed a nearly threefold change in temperature over a two year period. Although the researchers are quick to point out that the cause of the variability is still under investigation, they believe the readings could be due to massive amounts of volcanic activity on the surface. The ability to peek into the atmospheres of rocky ‘super Earths’ and observe conditions on their surfaces marks an important milestone towards identifying habitable planets outside the solar system.

Using NASA’s Spitzer Space Telescope, the researchers observed thermal emissions coming from the planet, called 55 Cancri e – orbiting a sun-like star located 40 light years away in the Cancer constellation – and for the first time found rapidly changing conditions, with temperatures on the hot ‘day’ side of the planet swinging between 1000 and 2700 degrees Celsius.

“This is the first time we’ve seen such drastic changes in light emitted from an exoplanet, which is particularly remarkable for a super Earth,” said Dr Nikku Madhusudhan of Cambridge’s Institute of Astronomy, a co-author on the new study. “No signature of thermal emissions or surface activity has ever been detected for any other super Earth to date.”

Although the interpretations of the new data are still preliminary, the researchers believe the variability in temperature could be due to huge plumes of gas and dust which occasionally blanket the surface, which may be partially molten. The plumes could be caused by exceptionally high rates of volcanic activity, higher than what has been observed on Io, one of Jupiter’s moons and the most geologically active body in the solar system.

“We saw a 300 percent change in the signal coming from this planet, which is the first time we’ve seen such a huge level of variability in an exoplanet,” said Dr Brice-Olivier Demory of the University’s Cavendish Laboratory, lead author of the new study. “While we can’t be entirely sure, we think a likely explanation for this variability is large-scale surface activity, possibly volcanism, on the surface is spewing out massive volumes of gas and dust, which sometimes blanket the thermal emission from the planet so it is not seen from Earth.”

55 Cancri e is a ‘super Earth’: a rocky exoplanet about twice the size and eight times the mass of Earth. It is one of five planets orbiting a sun-like star in the Cancer constellation, and resides so close to its parent star that a year lasts just 18 hours. The planet is also tidally locked, meaning that it doesn’t rotate like the Earth does – instead there is a permanent ‘day’ side and a ‘night’ side. Since it is the nearest super Earth whose atmosphere can be studied, 55 Cancri e is among the best candidates for detailed observations of surface and atmospheric conditions on rocky exoplanets.

Most of the early research on exoplanets has been on gas giants similar to Jupiter and Saturn, since their enormous size makes them easier to find. In recent years, astronomers have been able to map the conditions on many of these gas giants, but it is much more difficult to do so for super Earths: exoplanets with masses between one and ten times the mass of Earth.

Earlier observations of 55 Cancri e pointed to an abundance of carbon, suggesting that the planet was composed of diamond. However, these new results have muddied those earlier observations considerably and opened up new questions.

“When we first identified this planet, the measurements supported a carbon-rich model,” said Madhusudhan, who along with Demory is a member of the Cambridge Exoplanet Research Centre. “But now we’re finding that those measurements are changing in time. The planet could still be carbon rich, but now we’re not so sure – earlier studies of this planet have even suggested that it could be a water world. The present variability is something we’ve never seen anywhere else, so there’s no robust conventional explanation. But that’s the fun in science – clues can come from unexpected quarters. The present observations open a new chapter in our ability to study the conditions on rocky exoplanets using current and upcoming large telescopes.”

The results have been published online today.

The study was also co-authored by Professor Didier Queloz of the Cavendish Laboratory and Dr Michaël Gillon of the Université of Liège.

Astronomers have detected wildly changing temperatures on a super Earth – the first time any atmospheric variability has been observed on a rocky planet outside the solar system – and believe it could be due to huge amounts of volcanic activity, further adding to the mystery of what had been nicknamed the ‘diamond planet’.

This is the first time we’ve seen such drastic changes in light emitted from an exoplanetNikku MadhusudhanNASA/JPL-Caltech/R. HurtArtist’s impression of super-Earth 55 Cancri e, showing a hot partially-molten surface of the planet before and after possible volcanic activity on the day side.

The text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.


The human universe: Should we take responsibility for the cosmos?

5 May 2015 - 11:48am

We are the most powerful species in the known universe, and with great power comes great responsibility. We ask the experts what our role should be

Land ho: NASA spacecraft may have seen polar ice cap on Pluto

5 May 2015 - 11:47am

NASA's New Horizons spacecraft is 98 per cent of the way to Pluto, and it's getting better pictures than Hubble

NASA's Messenger probe crashes into Mercury making giant crater

5 May 2015 - 11:47am
After exhausting its fuel spending four years orbiting the nearest planet to the sun, Messenger has crashed, creating a 16-kilometre crater

NASA's Messenger probe crashes into Mercury

5 May 2015 - 11:47am

After exhausting its fuel spending four years orbiting the nearest planet to the sun, Messenger has crashed, creating a 16-metre crater

Mercury mission ends with a bang

5 May 2015 - 11:25am

After a decade in space and four years in orbit, Nasa's Messenger spacecraft reaches the end of its mission and crashes into the surface of Mercury.

Seeking comet splatter on Mercury

5 May 2015 - 11:25am

UK scientists hunt for comet remains on Mercury

NASA's NuSTAR Captures Possible 'Screams' from Zombie Stars

30 April 2015 - 9:41am
Peering into the heart of the Milky Way galaxy, NASA's Nuclear Spectroscopic Telescope Array (NuSTAR) has spotted a mysterious glow of high-energy X-rays that, according to scientists, could be the "howls" of dead stars as they feed on stellar companions.

NASA’s New Horizons Detects Surface Features, Possible Polar Cap on Pluto

30 April 2015 - 9:41am
For the first time, images from NASA’s New Horizons spacecraft are revealing bright and dark regions on the surface of faraway Pluto – the primary target of the New Horizons close flyby in mid-July.

The human universe: Exploring our place in space

30 April 2015 - 9:39am
We’re masters of Earth, but how do we measure up against the cosmos? From colonising stars to destroying the universe, we explore humans' role beyond our world

Milky Way's quiet life leaves it with no dark matter skeleton

30 April 2015 - 9:38am

Our galaxy has only ever merged with small galaxies, not large ones. This low-key history has left it bereft of dark matter from outside

Extended hard-X-ray emission in the inner few parsecs of the Galaxy

30 April 2015 - 9:36am

Extended hard-X-ray emission in the inner few parsecs of the Galaxy

Nature 520, 7549 (2015). doi:10.1038/nature14353

Authors: Kerstin Perez, Charles J. Hailey, Franz E. Bauer, Roman A. Krivonos, Kaya Mori, Frederick K. Baganoff, Nicolas M. Barrière, Steven E. Boggs, Finn E. Christensen, William W. Craig, Brian W. Grefenstette, Jonathan E. Grindlay, Fiona A. Harrison, Jaesub Hong, Kristin K. Madsen, Melania Nynka, Daniel Stern, John A. Tomsick, Daniel R. Wik, Shuo Zhang, William W. Zhang & Andreas Zoglauer

The Galactic Centre hosts a puzzling stellar population in its inner few parsecs, with a high abundance of surprisingly young, relatively massive stars bound within the deep potential well of the central supermassive black hole, Sagittarius A* (ref. 1). Previous studies suggest that the population of objects emitting soft X-rays (less than 10 kiloelectronvolts) within the surrounding hundreds of parsecs, as well as the population responsible for unresolved X-ray emission extending along the Galactic plane, is dominated by accreting white dwarf systems. Observations of diffuse hard-X-ray (more than 10 kiloelectronvolts) emission in the inner 10 parsecs, however, have been hampered by the limited spatial resolution of previous instruments. Here we report the presence of a distinct hard-X-ray component within the central 4 × 8 parsecs, as revealed by subarcminute-resolution images in the 20–40 kiloelectronvolt range. This emission is more sharply peaked towards the Galactic Centre than is the surface brightness of the soft-X-ray population. This could indicate a significantly more massive population of accreting white dwarfs, large populations of low-mass X-ray binaries or millisecond pulsars, or particle outflows interacting with the surrounding radiation field, dense molecular material or magnetic fields. However, all these interpretations pose significant challenges to our understanding of stellar evolution, binary formation, and cosmic-ray production in the Galactic Centre.

Astronomy: Light direct from an alien world

30 April 2015 - 9:29am

Astronomy: Light direct from an alien world

Nature 520, 7549 (2015). doi:10.1038/520588b

Astronomers have spotted light reflected off a planet orbiting a distant sun, by teasing it out from the background starlight. The discovery allows direct calculations of the mass and other properties of the exoplanet, rather than inferring them using other methods.Jorge Martins of the