Institute of Astronomy

Feed aggregator

Mars' ionosphere shaped by crustal magnetic fields

Astronomy News - 8 November 2016 - 9:39am

Scattered pockets of magnetism across the surface of Mars have a significant influence on the planet's upper atmosphere, according to observations from ESA's Mars Express. Understanding these effects may be crucial for ensuring safe radio communications between Mars and Earth and, eventually, between explorers on the surface of the planet.

Pasta spirals link neutron stars and the machinery of your cells

Astronomy News - 7 November 2016 - 9:19am

A balancing act between forces forms similar structures inside cells and dense stellar corpses, suggesting links between astrophysics and life on Earth

Mickey Mouse ears may explain universe’s biggest explosions

Astronomy News - 7 November 2016 - 9:18am

About a third of supernova remnants have bulging protuberances called "ears" - and these cute features could be key to understanding how supernovae are detonated

Pillars of Destruction

Astronomy News - 4 November 2016 - 9:38am
Spectacular new observations of vast pillar-like structures within the Carina Nebula have been made using the MUSE instrument on ESO’s Very Large Telescope. The different pillars analysed by an international team seem to be pillars of destruction — in contrast to the name of the iconic Pillars of Creation in the Eagle Nebula, which are of similar nature.

Formation of new stellar populations from gas accreted by massive young star clusters

Astronomy News - 4 November 2016 - 9:38am

Formation of new stellar populations from gas accreted by massive young star clusters

Nature 539, 7627 (2016). doi:10.1038/nature19336

Author: Chengyuan Li, Richard de Grijs, Licai Deng, Aaron M. Geller, Yu Xin, Yi Hu & Claude-André Faucher-Giguère

Nature529, 502–504 (2016); doi:10.1038/nature16493Following publication of this Letter, we were made aware that the target cluster identified as ‘NGC 1696’ is instead the cluster ‘NGC 1806’. This mistake was caused by a misidentification in the Hubble

The formation of Charon’s red poles from seasonally cold-trapped volatiles

Astronomy News - 4 November 2016 - 9:38am

The formation of Charon’s red poles from seasonally cold-trapped volatiles

Nature 539, 7627 (2016). doi:10.1038/nature19340

Authors: W. M. Grundy, D. P. Cruikshank, G. R. Gladstone, C. J. A. Howett, T. R. Lauer, J. R. Spencer, M. E. Summers, M. W. Buie, A. M. Earle, K. Ennico, J. Wm. Parker, S. B. Porter, K. N. Singer, S. A. Stern, A. J. Verbiscer, R. A. Beyer, R. P. Binzel, B. J. Buratti, J. C. Cook, C. M. Dalle Ore, C. B. Olkin, A. H. Parker, S. Protopapa, E. Quirico, K. D. Retherford, S. J. Robbins, B. Schmitt, J. A. Stansberry, O. M. Umurhan, H. A. Weaver, L. A. Young, A. M. Zangari, V. J. Bray, A. F. Cheng, W. B. McKinnon, R. L. McNutt, J. M. Moore, F. Nimmo, D. C. Reuter & P. M. Schenk

A unique feature of Pluto’s large satellite Charon is its dark red northern polar cap. Similar colours on Pluto’s surface have been attributed to tholin-like organic macromolecules produced by energetic radiation processing of hydrocarbons. The polar location on Charon implicates the temperature extremes that result from Charon’s high obliquity and long seasons in the production of this material. The escape of Pluto’s atmosphere provides a potential feedstock for a complex chemistry. Gas from Pluto that is transiently cold-trapped and processed at Charon’s winter pole was proposed as an explanation for the dark coloration on the basis of an image of Charon’s northern hemisphere, but not modelled quantitatively. Here we report images of the southern hemisphere illuminated by Pluto-shine and also images taken during the approach phase that show the northern polar cap over a range of longitudes. We model the surface thermal environment on Charon and the supply and temporary cold-trapping of material escaping from Pluto, as well as the photolytic processing of this material into more complex and less volatile molecules while cold-trapped. The model results are consistent with the proposed mechanism for producing the observed colour pattern on Charon.

Bridge the planetary divide

Astronomy News - 4 November 2016 - 9:36am

Bridge the planetary divide

Nature 539, 7627 (2016). doi:10.1038/539025a

Authors: Ariel D. Anbar, Christy B. Till & Mark A. Hannah

To explain why our planet is habitable, geoscientists studying Earth’s surface and interior must work with each other and with communications scholars, write Ariel D. Anbar, Christy B. Till and Mark A. Hannah.

Astronomy: Small stars host water worlds

Astronomy News - 4 November 2016 - 9:36am

Astronomy: Small stars host water worlds

Nature 539, 7627 (2016). doi:10.1038/539008d

Earth-sized planets covered in water may be abundant around red dwarfs, the most common type of star in the Universe.Yann Alibert and Willy Benz at the University of Bern used computer simulations to predict the properties of planets that could form around red dwarfs

James Webb: Two years to Hubble successor's launch

Astronomy News - 4 November 2016 - 9:32am

Engineers finish assembling the telescope that will succeed Hubble. James Webb, as it is known, is now on track to be launched two years from now.

Biggest telescope may switch location

Astronomy News - 2 November 2016 - 9:12am

One of the world's biggest telescope projects might be forced to move its location.

Space telescope duo will showcase the solar system in 3D

Astronomy News - 1 November 2016 - 9:15am

From 2019 to 2021, the Hubble and James Webb telescopes will share the sky, enabling us to see the best 3D images and movies of our celestial neighbourhood ever

Follow the Gaia 2016 Data Release #1 Workshop live

Astronomy News - 31 October 2016 - 9:43am
On 2-4 November, the European Space Astronomy Centre near Madrid, Spain, will host the Gaia 2016 Data Release #1 Workshop. Many of the talks will be broadcast live.

Gaia spies two temporarily magnified stars

Astronomy News - 28 October 2016 - 9:19am

While scanning the sky to measure the position of over one billion stars in our Galaxy, ESA's Gaia satellite has detected two rare instances of stars whose light was temporarily boosted by other celestial objects passing across their lines of sight. One of these stars is expected to brighten again soon. Gaia's measurements will be instrumental to learn more about the nature of these 'cosmic magnifying glasses'.

A Death Star's Ghostly Glow

Astronomy News - 28 October 2016 - 9:19am

Get larger image formats

In writer Edgar Allan Poe's short story "The Tell-Tale Heart," a killer confesses his crime after he thinks he hears the beating of his victim's heart. The heartbeat turns out to be an illusion. Astronomers, however, discovered a real "tell-tale heart" in space, 6,500 light-years from Earth. The "heart" is the crushed core of a long-dead star, called a neutron star, which exploded as a supernova and is now still beating with rhythmic precision. Evidence of its heartbeat are rapid-fire, lighthouse-like pulses of energy from the fast-spinning neutron star. The stellar relic is embedded in the center of the Crab Nebula, the expanding, tattered remains of the doomed star.

Images reveal crashed Mars lander

Astronomy News - 28 October 2016 - 9:15am

The site where Europe's Mars lander crashed this month is revealed in new images.

Potassium isotopic evidence for a high-energy giant impact origin of the Moon

Astronomy News - 27 October 2016 - 8:13am

Potassium isotopic evidence for a high-energy giant impact origin of the Moon

Nature 538, 7626 (2016). doi:10.1038/nature19341

Authors: Kun Wang & Stein B. Jacobsen

The Earth–Moon system has unique chemical and isotopic signatures compared with other planetary bodies; any successful model for the origin of this system therefore has to satisfy these chemical and isotopic constraints. The Moon is substantially depleted in volatile elements such as potassium compared with the Earth and the bulk solar composition, and it has long been thought to be the result of a catastrophic Moon-forming giant impact event. Volatile-element-depleted bodies such as the Moon were expected to be enriched in heavy potassium isotopes during the loss of volatiles; however such enrichment was never found. Here we report new high-precision potassium isotope data for the Earth, the Moon and chondritic meteorites. We found that the lunar rocks are significantly (>2σ) enriched in the heavy isotopes of potassium compared to the Earth and chondrites (by around 0.4 parts per thousand). The enrichment of the heavy isotope of potassium in lunar rocks compared with those of the Earth and chondrites can be best explained as the result of the incomplete condensation of a bulk silicate Earth vapour at an ambient pressure that is higher than 10 bar. We used these coupled constraints of the chemical loss and isotopic fractionation of K to compare two recent dynamic models that were used to explain the identical non-mass-dependent isotope composition of the Earth and the Moon. Our K isotope result is inconsistent with the low-energy disk equilibration model, but supports the high-energy, high-angular-momentum giant impact model for the origin of the Moon. High-precision potassium isotope data can also be used as a ‘palaeo-barometer’ to reveal the physical conditions during the Moon-forming event.

Icy heart could be key to Pluto’s strange geology

Astronomy News - 27 October 2016 - 8:12am

Icy heart could be key to Pluto’s strange geology

Nature 538, 7626 (2016).

Author: Alexandra Witze

NASA’s New Horizons mission plumbs complex interplay between the dwarf planet's surface and its sky.

Astrophysics: Birth of stellar siblings

Astronomy News - 27 October 2016 - 8:11am

Astrophysics: Birth of stellar siblings

Nature 538, 7626 (2016). doi:10.1038/538466a

Authors: Adele Plunkett

Binary and multiple star systems result from the fragmentation of dense material in young molecular clouds. Observations reveal that this can occur on small scales, supporting a previous model of star formation. See Letter p.483

A triple protostar system formed via fragmentation of a gravitationally unstable disk

Astronomy News - 27 October 2016 - 8:11am

A triple protostar system formed via fragmentation of a gravitationally unstable disk

Nature 538, 7626 (2016). doi:10.1038/nature20094

Authors: John J. Tobin, Kaitlin M. Kratter, Magnus V. Persson, Leslie W. Looney, Michael M. Dunham, Dominique Segura-Cox, Zhi-Yun Li, Claire J. Chandler, Sarah I. Sadavoy, Robert J. Harris, Carl Melis & Laura M. Pérez

Binary and multiple star systems are a frequent outcome of the star formation process and as a result almost half of all stars with masses similar to that of the Sun have at least one companion star. Theoretical studies indicate that there are two main pathways that can operate concurrently to form binary/multiple star systems: large-scale fragmentation of turbulent gas cores and filaments or smaller-scale fragmentation of a massive protostellar disk due to gravitational instability. Observational evidence for turbulent fragmentation on scales of more than 1,000 astronomical units has recently emerged. Previous evidence for disk fragmentation was limited to inferences based on the separations of more-evolved pre-main sequence and protostellar multiple systems. The triple protostar system L1448 IRS3B is an ideal system with which to search for evidence of disk fragmentation as it is in an early phase of the star formation process, it is likely to be less than 150,000 years old and all of the protostars in the system are separated by less than 200 astronomical units. Here we report observations of dust and molecular gas emission that reveal a disk with a spiral structure surrounding the three protostars. Two protostars near the centre of the disk are separated by 61 astronomical units and a tertiary protostar is coincident with a spiral arm in the outer disk at a separation of 183 astronomical units. The inferred mass of the central pair of protostellar objects is approximately one solar mass, while the disk surrounding the three protostars has a total mass of around 0.30 solar masses. The tertiary protostar itself has a minimum mass of about 0.085 solar masses. We demonstrate that the disk around L1448 IRS3B appears susceptible to disk fragmentation at radii between 150 and 320 astronomical units, overlapping with the location of the tertiary protostar. This is consistent with models for a protostellar disk that has recently undergone gravitational instability, spawning one or two companion stars.

ESO’s VLT Detects Unexpected Giant Glowing Halos around Distant Quasars

Astronomy News - 27 October 2016 - 8:07am
An international team of astronomers has discovered glowing gas clouds surrounding distant quasars. This new survey by the MUSE instrument on ESO’s Very Large Telescope indicates that halos around quasars are far more common than expected. The properties of the halos in this surprising find are also in striking disagreement with currently accepted theories of galaxy formation in the early Universe.