Institute of Astronomy

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ALMA Starts Observing the Sun

Astronomy News - 18 January 2017 - 9:23am
New images taken with the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile have revealed otherwise invisible details of our Sun, including a new view of the dark, contorted centre of a sunspot that is nearly twice the diameter of the Earth. The images are the first ever made of the Sun with a facility where ESO is a partner. The results are an important expansion of the range of observations that can be used to probe the physics of our nearest star. The ALMA antennas had been carefully designed so they could image the Sun without being damaged by the intense heat of the focussed light.

Binary stars shred up and shove off their newborn planets

Astronomy News - 17 January 2017 - 9:45am

There are more pairs of stars than solo stars in our galaxy, but fewer pairs host planets. Now we have an idea why: they rip them to shreds

Cold case: The unsolved mystery of what lit Kepler’s supernova

Astronomy News - 17 January 2017 - 9:44am

In 1604, the last Milky Way supernova recorded by naked-eye observers brightened the night sky. Despite 400 years of study, we still don't know what lit the fuse

Complex life may have had a false start 2.3 billion years ago

Astronomy News - 17 January 2017 - 9:44am

High levels of oceanic oxygen could have allowed advanced, animal-like life to develop for the first time – only to be wiped out again as oxygen vanished

ESA Planetary Science Archive gets a new look

Astronomy News - 17 January 2017 - 9:42am

Today, ESA launches a new version of its Planetary Science Archive (PSA) website, the online interface to data from the agency's space science missions that have been exploring planets, moons and other small bodies in the Solar System. With a new design and enhanced search functionalities, the platform now provides a direct and simple access to the scientific data, helping scientists to discover and explore the archive content.

Venus wave may be Solar System's biggest

Astronomy News - 17 January 2017 - 9:42am

A giant wave in the atmosphere of Venus may be the biggest of its kind in the Solar System.

Penitentes as the origin of the bladed terrain of Tartarus Dorsa on Pluto

Astronomy News - 12 January 2017 - 1:36pm

Penitentes as the origin of the bladed terrain of Tartarus Dorsa on Pluto

Nature 541, 7636 (2017). doi:10.1038/nature20779

Authors: John E. Moores, Christina L. Smith, Anthony D. Toigo & Scott D. Guzewich

Penitentes are snow and ice features formed by erosion that, on Earth, are characterized by bowl-shaped depressions several tens of centimetres across, whose edges grade into spires up to several metres tall. Penitentes have been suggested as an explanation for anomalous radar data on Europa, but until now no penitentes have been identified conclusively on planetary bodies other than Earth. Regular ridges with spacings of 3,000 to 5,000 metres and depths of about 500 metres with morphologies that resemble penitentes have been observed by the New Horizons spacecraft in the Tartarus Dorsa region of Pluto (220°–250° E, 0°–20° N). Here we report simulations, based upon a recent model representing conditions on Pluto, in which deepening penitentes reproduce both the tri-modal (north–south, east–west and northeast–southwest) orientation and the spacing of the ridges of this bladed terrain. At present, these penitentes deepen by approximately one centimetre per orbital cycle and grow only during periods of relatively high atmospheric pressure, suggesting a formation timescale of several tens of millions of years, consistent with crater ages. This timescale implies that the penitentes formed from initial topographic variations of no more than a few tens of metres, consistent with Pluto’s youngest terrains.

Legendary radio telescope hangs in the balance

Astronomy News - 12 January 2017 - 1:35pm

Legendary radio telescope hangs in the balance

Nature 541, 7636 (2017). http://www.nature.com/doifinder/10.1038/541143a

Author: Alexandra Witze

US National Science Foundation looks to slash funding for Puerto Rico’s Arecibo Observatory.

Planetary science: Many collisions made the Moon

Astronomy News - 12 January 2017 - 1:34pm

Planetary science: Many collisions made the Moon

Nature 541, 7636 (2017). doi:10.1038/541137e

The Moon may have been formed not from one big cosmic smash, as the leading theory holds, but from multiple smaller collisions.Billions of years ago in the early Solar System, space debris would have collided with the young Earth. Using computer simulations, a team

China plans telescope to hunt for primordial gravitational waves

Astronomy News - 12 January 2017 - 1:33pm
Located at 5250 metres above sea level in Tibet, Ngari-1 will hunt for gravitational waves that should have been thrown out by the big bang

‘Alien megastructure’ signal may be due to star eating a planet

Astronomy News - 10 January 2017 - 9:24am

Tabby’s star’s odd blinking and fading has been put down to alien signals and swarms of comets, but devouring a planet could explain everything

New candidate for 'missing element' in Earth's core

Astronomy News - 10 January 2017 - 9:21am

Scientists believe they have established the identity of a "missing element" in the Earth's core.

Milky Way’s core could be spewing out planet-sized star chunks

Astronomy News - 9 January 2017 - 9:32am

The supermassive black hole at the galaxy's heart can stretch and shred stars that approach – then fling the shreds away as spheres as small as Neptune

Stephen Hawking says he has a way to escape from a black hole

Astronomy News - 9 January 2017 - 9:31am

Researchers have long struggled to resolve what happens to information when it falls inside a black hole, but the famous physicist says he has a solution

Hubble Captures 'Shadow Play' Caused by Possible Planet

Astronomy News - 9 January 2017 - 9:31am

Eerie mysteries in the universe can be betrayed by simple shadows. The wonder of a solar eclipse is produced by the moon's shadow, and over 1,000 planets around other stars have been cataloged by the shadow they cast when passing in front of their parent star. Astronomers were surprised to see a huge shadow sweeping across a disk of dust and gas encircling a nearby, young star. They have a bird's-eye view of the disk, because it is tilted face-on to Earth, and the shadow sweeps around the disk like the hands moving around a clock. But, unlike the hands of a clock, the shadow takes 16 years to make one rotation.

Hubble has 18 years' worth of observations of the star, called TW Hydrae. Therefore, astronomers could assemble a time-lapse movie of the shadow's rotation. Explaining it is another story. Astronomers think that an unseen planet in the disk is doing some heavy lifting by gravitationally pulling on material near the star and warping the inner part of the disk. The twisted, misaligned inner disk is casting its shadow across the surface of the outer disk. TW Hydrae resides 192 light-years away and is roughly 8 million years old.

Mars should have loads more water – so where has it all gone?

Astronomy News - 6 January 2017 - 9:17am

We have either misunderstood what its early years were like – or it is hiding vast amounts of water beneath its surface

A direct localization of a fast radio burst and its host

Astronomy News - 5 January 2017 - 9:23am

A direct localization of a fast radio burst and its host

Nature 541, 7635 (2017). doi:10.1038/nature20797

Authors: S. Chatterjee, C. J. Law, R. S. Wharton, S. Burke-Spolaor, J. W. T. Hessels, G. C. Bower, J. M. Cordes, S. P. Tendulkar, C. G. Bassa, P. Demorest, B. J. Butler, A. Seymour, P. Scholz, M. W. Abruzzo, S. Bogdanov, V. M. Kaspi, A. Keimpema, T. J. W. Lazio, B. Marcote, M. A. McLaughlin, Z. Paragi, S. M. Ransom, M. Rupen, L. G. Spitler & H. J. van Langevelde

Fast radio bursts are astronomical radio flashes of unknown physical nature with durations of milliseconds. Their dispersive arrival times suggest an extragalactic origin and imply radio luminosities that are orders of magnitude larger than those of all known short-duration radio transients. So far all fast radio bursts have been detected with large single-dish telescopes with arcminute localizations, and attempts to identify their counterparts (source or host galaxy) have relied on the contemporaneous variability of field sources or the presence of peculiar field stars or galaxies. These attempts have not resulted in an unambiguous association with a host or multi-wavelength counterpart. Here we report the subarcsecond localization of the fast radio burst FRB 121102, the only known repeating burst source, using high-time-resolution radio interferometric observations that directly image the bursts. Our precise localization reveals that FRB 121102 originates within 100 milliarcseconds of a faint 180-microJansky persistent radio source with a continuum spectrum that is consistent with non-thermal emission, and a faint (twenty-fifth magnitude) optical counterpart. The flux density of the persistent radio source varies by around ten per cent on day timescales, and very long baseline radio interferometry yields an angular size of less than 1.7 milliarcseconds. Our observations are inconsistent with the fast radio burst having a Galactic origin or its source being located within a prominent star-forming galaxy. Instead, the source appears to be co-located with a low-luminosity active galactic nucleus or a previously unknown type of extragalactic source. Localization and identification of a host or counterpart has been essential to understanding the origins and physics of other kinds of transient events, including gamma-ray bursts and tidal disruption events. However, if other fast radio bursts have similarly faint radio and optical counterparts, our findings imply that direct subarcsecond localizations may be the only way to provide reliable associations.

Astronomy: Radio burst caught red-handed

Astronomy News - 5 January 2017 - 9:23am

Astronomy: Radio burst caught red-handed

Nature 541, 7635 (2017). doi:10.1038/541032a

Authors: Heino Falcke

For almost a decade, astronomers have observed intense bursts of radio waves from the distant cosmos whose origins were unknown. The source of one such burst has now been identified, but this has only deepened the mystery. See Letter p.58

Publishing: A brief history of Stephen Hawking's blockbuster

Astronomy News - 5 January 2017 - 9:22am

Publishing: A brief history of Stephen Hawking's blockbuster

Nature 541, 7635 (2017). doi:10.1038/nature16881

Author: Elizabeth Leane

Elizabeth Leane surveys the extraordinary influence of the physicist's first foray into popular-science publishing.

Cosmic radio bursts tracked to home galaxy for first time

Astronomy News - 5 January 2017 - 9:21am

One repeating example of a fast radio burst has finally been pinned down to a tiny and distant dwarf galaxy, narrowing down its precise origin