Institute of Astronomy

Feed aggregator

What a Red Planet aurora might look like

Astronomy News - 2 June 2015 - 9:06am

Fancy seeing a blue light show? A simulation of the Martian atmosphere reveals what an aurora might look like to the naked eye







#RosettaWatch: 67P formed when two baby comets got together

Astronomy News - 1 June 2015 - 9:49am
A gentle dance involving two chunks of dirty ice may explain the distinctive duck-like shape of the Rosetta probe's quarry







Who are we now?. (arXiv:1505.08051v1 [astro-ph.IM])

Astronomy News - 1 June 2015 - 9:44am

In 2014 the Royal Astronomical Society carried out a survey of its membership, finding that we are both more and less diverse than UK society as a whole. Robert Massey summarizes the findings and what they mean for the Society in future.

Herschel's hunt for filaments in the Milky Way

Astronomy News - 29 May 2015 - 10:21am

Observations with ESA's Herschel space observatory have revealed that our Galaxy is threaded with filamentary structures on every length scale. From nearby clouds hosting tangles of filaments a few light-years long to gigantic structures stretching hundreds of light-years across the Milky Way's spiral arms, they appear to be truly ubiquitous. The Herschel data have rekindled the interest of astronomers in studying filaments, emphasising the crucial role of these structures in the process of star formation.

Merging galaxies break radio silence [heic1511]

Astronomy News - 29 May 2015 - 10:14am

In the most extensive survey of its kind ever conducted, a team of scientists have found an unambiguous link between the presence of supermassive black holes that power high-speed, radio-signal-emitting jets and the merger history of their host galaxies. Almost all of the galaxies hosting these jets were found to be merging with another galaxy, or to have done so recently. The results lend significant weight to the case for jets being the result of merging black holes and will be presented in the Astrophysical Journal.

NASA to Hold Media Call to Discuss Surprising Observations of Pluto’s Moons

Astronomy News - 29 May 2015 - 10:13am
NASA will host a media teleconference at 1 p.m. EDT on Wednesday, June 3, to discuss the Hubble Space Telescope’s surprising observations of how Pluto’s moons behave, and how these new discoveries are being used in the planning for the New Horizons Pluto flyby in July.

Mars lander gets set for mission to probe planet's depths

Astronomy News - 29 May 2015 - 10:12am

NASA's InSight rover is being put through its paces in preparation for its trip to Mars next year







Black hole seen 'playing billiards'

Astronomy News - 29 May 2015 - 9:59am

A series of images captures two vast blobs of plasma, shot out by a black hole, cannoning into each other in a nearly light-speed cosmic collision.

A Bubbly Cosmic Celebration

Astronomy News - 28 May 2015 - 10:40am
In the brightest region of this glowing nebula called RCW 34, gas is heated dramatically by young stars and expands through the surrounding cooler gas. Once the heated hydrogen reaches the borders of the gas cloud, it bursts outwards into the vacuum like the contents of an uncorked champagne bottle — this process is referred to as champagne flow. But the young star-forming region RCW 34 has more to offer than a few bubbles; there seem to have been multiple episodes of star formation within the same cloud.

Hubble Video Shows Shock Collision Inside Black Hole Jet

Astronomy News - 28 May 2015 - 10:39am

Get larger image formats

One of the trademarks of the Star Wars film episodes is the dreaded Death Star battle station that fires a beam of directed energy powerful enough to blow up planets. The real universe has such fireworks, and they are vastly more powerful than the Star Wars creation. These extragalactic jets are tearing across hundreds of light-years of space at 98 percent the speed of light. Instead of a battle station, the source of the killer beam is a supermassive black hole weighing many million or even a billion times the mass of our sun. Energy from the spinning black hole, and its titanic magnetic fields, shape a narrow jet of gas blasting out a galaxy's center. Hubble has been used over the past 25 years to photograph and rephotograph a jet blasting out the heart of the elliptical galaxy 3C 264 (also known as NGC 3862). Hubble's sharp vision reveals that the jet has a string-of-pearls structure of glowing knots of material. When these images were assembled into a time-lapse movie, they reveal to the surprise of astronomers a faster-moving bright knot rear-ending the bright knot in front of it. The resulting shock collision further accelerates particles that produce a focused beam of deadly radiation. The jet is moving so fast toward us it gives the illusion that it is traveling faster than the speed of light. But not to worry, the host galaxy is 260 million light-years away. We are seeing the jet as it looked before the dinosaurs appeared on Earth, and our planet was suffering a global mass extinction.

A kiloparsec-scale internal shock collision in the jet of a nearby radio galaxy

Astronomy News - 28 May 2015 - 10:36am

A kiloparsec-scale internal shock collision in the jet of a nearby radio galaxy

Nature 521, 7553 (2015). doi:10.1038/nature14481

Authors: Eileen T. Meyer, Markos Georganopoulos, William B. Sparks, Eric Perlman, Roeland P. van der Marel, Jay Anderson, Sangmo Tony Sohn, John Biretta, Colin Norman & Marco Chiaberge

Jets of highly energized plasma with relativistic velocities are associated with black holes ranging in mass from a few times that of the Sun to the billion-solar-mass black holes at the centres of galaxies. A popular but unconfirmed hypothesis to explain how the plasma is energized is the ‘internal shock model’, in which the relativistic flow is unsteady. Faster components in the jet catch up to and collide with slower ones, leading to internal shocks that accelerate particles and generate magnetic fields. This mechanism can explain the variable, high-energy emission from a diverse set of objects, with the best indirect evidence being the unseen fast relativistic flow inferred to energize slower components in X-ray binary jets. Mapping of the kinematic profiles in resolved jets has revealed precessing and helical patterns in X-ray binaries, apparent superluminal motions, and the ejection of knots (bright components) from standing shocks in the jets of active galaxies. Observations revealing the structure and evolution of an internal shock in action have, however, remained elusive, hindering measurement of the physical parameters and ultimate efficiency of the mechanism. Here we report observations of a collision between two knots in the jet of nearby radio galaxy 3C 264. A bright knot with an apparent speed of (7.0 ± 0.8)c, where c is the speed of light in a vacuum, is in the incipient stages of a collision with a slower-moving knot of speed (1.8 ± 0.5)c just downstream, resulting in brightening of both knots—as seen in the most recent epoch of imaging.

Discovery shows what the solar system looked like as a ‘toddler’

Astronomy News - 27 May 2015 - 10:15am

An international team of astronomers, including researchers from the University of Cambridge, has identified a young planetary system which may aid in understanding how our own solar system formed and developed billions of years ago.

Using the Gemini Planet Imager (GPI) at the Gemini South telescope in Chile, the researchers identified a disc-shaped bright ring of dust around a star only slightly more massive than the sun, located 360 light years away in the Centaurus constellation. The disc is located between about 37 and 55 Astronomical Units (3.4 – 5.1 billion miles) from its host star, which is almost the same distance as the solar system’s Kuiper Belt is from the sun. The brightness of the disc, which is due to the starlight reflected by it, is also consistent with a wide range of dust compositions including the silicates and ice present in the Kuiper Belt.

The Kuiper Belt lies just beyond Neptune, and contains thousands of small icy bodies left over from the formation of the solar system more than four billion years ago. These objects range in size from specks of debris dust, all the way up to moon-sized objects like Pluto – which used to be classified as a planet, but has now been reclassified as a dwarf planet.

The star observed in this new study is a member of the massive 10-20 million year-old Scorpius-Centaurus OB association, a region similar to that in which the sun was formed. The disc is not perfectly centred on the star, which is strong indication that it was likely sculpted by one or more unseen planets. By using models of how planets shape a debris disc, the team found that ‘eccentric’ versions of the giant planets in the outer solar system could explain the observed properties of the ring.

“It’s almost like looking at the outer solar system when it was a toddler,” said principal investigator Thayne Currie, an astronomer at the Subaru Observatory in Hawaii.

The current theory on the formation of the solar system holds that it originated within a giant molecular cloud of hydrogen, in which clumps of denser material formed. One of these clumps, rotating and collapsing under its own gravitation, formed a flattened spinning disc known as the solar nebula. The sun formed at the hot and dense centre of this disc, while the planets grew by accretion in the cooler outer regions. The Kuiper Belt is believed to be made up of the remnants of this process, so there is a possibility that once the new system develops, it may look remarkably similar to our solar system.

“To be able to directly image planetary birth environments around other stars at orbital distances comparable to the solar system is a major advancement,” said Dr Nikku Madhusudhan of Cambridge’s Institute of Astronomy, one of the paper’s co-authors. “Our discovery of a near-twin of the Kuiper Belt provides direct evidence that the planetary birth environment of the solar system may not be uncommon.”

This is the first discovery with the new cutting-edge Gemini instrument. “In just one of our many 50-second exposures we could see what previous instruments failed to see in more than 50 minutes,” said Currie.

The star, going by the designation HD 115600, was the first object the research team looked at. “Over the next few years, I’m optimistic that GPI will reveal many more debris discs and young planets. Who knows what strange, new worlds we will find,” Currie added.

The paper is accepted for publication in The Astrophysical Journal Letters

Astronomers have discovered a disc of planetary debris surrounding a young sun-like star that shares remarkable similarities with the Kuiper Belt that lies beyond Neptune, and may aid in understanding how our solar system developed.

Our discovery of a near-twin of the Kuiper Belt provides direct evidence that the planetary birth environment of the solar system may not be uncommonNikku MadhusudhanT. CurrieLeft: Image of HD 115600 showing a bright debris ring viewed nearly edge-on and located just beyond a Pluto-like distance to the star. Right: A model of the HD 115600 debris ring on the same scale.


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

Yes

Mission to Europa will test Jupiter moon's friendliness to life

Astronomy News - 27 May 2015 - 10:14am
NASA has announced the instruments for its next mission to Jupiter's icy moon Europa, one of the solar system's best candidates for hosting life







Einstein and Schrödinger: The price of fame

Astronomy News - 26 May 2015 - 10:44am

From personal feuds to fruitless quests to overhaul quantum theory, the two physics legends fought hard to maintain their fame, argues a new book







Getting an insight into Einstein's worlds

Astronomy News - 26 May 2015 - 10:41am

From a row about time to a bad paper on black holes, there's lots to learn about Einstein from a clutch of books published at the centenary of general relativity







Hubble Observes One-of-a-Kind Star Nicknamed 'Nasty'

Astronomy News - 22 May 2015 - 10:29am

Get larger image formats

Astronomers have spent decades trying to determine the oddball behavior of an aging star nicknamed "Nasty 1" residing in our Milky Way galaxy. Nasty 1 was identified as a Wolf-Rayet star, a rapidly evolving star that is much more massive than our sun. The star loses its hydrogen-filled outer layers quickly, exposing its super-hot and extremely bright helium-burning core.

NASA's WISE Spacecraft Discovers Most Luminous Galaxy in Universe

Astronomy News - 22 May 2015 - 10:28am
A remote galaxy shining with the light of more than 300 trillion suns has been discovered using data from NASA's Wide-field Infrared Survey Explorer (WISE). The galaxy is the most luminous galaxy found to date and belongs to a new class of objects recently discovered by WISE -- extremely luminous infrared galaxies, or ELIRGs.

NASA TV to Air Announcement of Instruments for Europa Mission

Astronomy News - 22 May 2015 - 10:28am
NASA will announce on Tuesday, May 26, the selection of science instruments for a mission to Europa, to investigate whether Jupiter’s icy moon could harbor conditions suitable for life.

Vesta has no moons – is it unlucky or did it eat them?

Astronomy News - 22 May 2015 - 10:26am
The second-heaviest asteroid in the solar system has no orbiting companions, even though hundreds of smaller asteroids do. Where did they go?







The Dreadful Beauty of Medusa

Astronomy News - 21 May 2015 - 10:28am
Astronomers using ESO’s Very Large Telescope in Chile have captured the most detailed image ever taken of the Medusa Nebula. As the star at the heart of this nebula made its transition into retirement, it shed its outer layers into space, forming this colourful cloud. The image foreshadows the final fate of the Sun, which will eventually also become an object of this kind.