The double-degenerate, super-Chandrasekhar nucleus of the planetary nebula Henize 2-428

Nature 519, 7541 (2015). doi:10.1038/nature14124

Authors: M. Santander-García, P. Rodríguez-Gil, R. L. M. Corradi, D. Jones, B. Miszalski, H. M. J. Boffin, M. M. Rubio-Díez & M. M. Kotze

The planetary nebula stage is the ultimate fate of stars with masses one to eight times that of the Sun (). The origin of their complex morphologies is poorly understood, although several mechanisms involving binary interaction have been proposed. In close binary systems, the orbital separation is short enough for the primary star to overfill its Roche lobe as the star expands during the asymptotic giant branch phase. The excess gas eventually forms a common envelope surrounding both stars. Drag forces then result in the envelope being ejected into a bipolar planetary nebula whose equator is coincident with the orbital plane of the system. Systems in which both stars have ejected their envelopes and are evolving towards the white dwarf stage are said to be double degenerate. Here we report that Henize 2-428 has a double-degenerate core with a combined mass of ∼1.76, which is above the Chandrasekhar limit (the maximum mass of a stable white dwarf) of 1.4. This, together with its short orbital period (4.2 hours), suggests that the system should merge in 700 million years, triggering a type Ia supernova event. This supports the hypothesis of the double-degenerate, super-Chandrasekhar evolutionary pathway for the formation of type Ia supernovae.

Astronomers have found that the growth of galaxies containing black holes can be slowed down by a phenomenon referred to as cosmic precipitation.

The huge eyes of the Large Binocular Telescope in Arizona are staring across vast cosmic distances in the hope of finding signs of alien life

The asteroid-hopping spacecraft will arrive at Ceres on Friday, making it the first to visit a dwarf planet and the first to visit two different worlds

One of the most distant galaxies ever observed has provided astronomers with the first detection of dust in such a remote star-forming system and tantalising evidence for the rapid evolution of galaxies after the Big Bang. The new observations have used ALMA to pick up the faint glow from cold dust in the galaxy A1689-zD1 and used ESO’s Very Large Telescope to measure its distance.

The quantum Casimir effect is a slight attraction between two metal plates. Superconducting versions could finally show us quantum gravity at work

As Nasa's Dawn satellite prepares to enter into orbit around the dwarf planet Ceres, scientists say they are excited to learn more about the two bright spots on its surface.

How Earth survived through violent times

The Rosetta satellite sees its own shadow in the highest resolution image it has so far taken of Comet 67P.

Cruising through the asteroid belt, NASA Dawn spacecraft is approaching dwarf planet Ceres, and some puzzling features are coming into focus. Researchers are especially mystified by a pair of bright spots.

Dwarf planet Ceres continues to puzzle scientists as NASA's Dawn spacecraft gets closer to being captured into orbit around the object. The latest images from Dawn, taken nearly 29,000 miles (46,000 kilometers) from Ceres, reveal that a bright spot that stands out in previous images lies close to yet another bright area.

UK industry completes construction of the modules that make up the Lisa Pathfinder satellite - a remarkable probe that will test the key technologies needed to detect gravitational waves in space.

Abstract submissions are now open for NAM 2015!

The National Astronomy Meeting (NAM) is the largest gathering of professional astronomers in the UK. Each year around 600 astronomers meet to present their research and discuss the latest developments in the field. This year NAM will be held in Llandudno, north Wales, from 5-9 July.

The deadline for submitting an abstract for a talk or poster presentation is 1 April.

http://nam2015.org/

The MUSE instrument on ESO’s Very Large Telescope has given astronomers the best ever three-dimensional view of the deep Universe. After staring at the Hubble Deep Field South region for only 27 hours, the new observations reveal the distances, motions and other properties of far more galaxies than ever before in this tiny piece of the sky. They also go beyond Hubble and reveal previously invisible objects.

A tale of two dwarf planets

Nature 518, 7540 (2015). http://www.nature.com/doifinder/10.1038/518468a

Author: Alex Witze

Graphical guide to the NASA missions that will provide the first close looks at Ceres and Pluto.

Planetary science: The Pluto siblings

Nature 518, 7540 (2015). http://www.nature.com/doifinder/10.1038/518470a

Author: Alexandra Witze

Leslie and Eliot Young have spent their lives studying Pluto. Now they are gearing up for the biggest event of their careers.

Cosmology: A giant in the young Universe

Nature 518, 7540 (2015). doi:10.1038/518490b

Authors: Bram Venemans

Astronomers have discovered an extremely massive black hole from a time when the Universe was less than 900 million years old. The result provides insight into the growth of black holes and galaxies in the young Universe. See Letter p.512

An ultraluminous quasar with a twelve-billion-solar-mass black hole at redshift 6.30

Nature 518, 7540 (2015). doi:10.1038/nature14241

Authors: Xue-Bing Wu, Feige Wang, Xiaohui Fan, Weimin Yi, Wenwen Zuo, Fuyan Bian, Linhua Jiang, Ian D. McGreer, Ran Wang, Jinyi Yang, Qian Yang, David Thompson & Yuri Beletsky

So far, roughly 40 quasars with redshifts greater than z = 6 have been discovered. Each quasar contains a black hole with a mass of about one billion solar masses (109). The existence of such black holes when the Universe was less than one billion years old presents substantial challenges to theories of the formation and growth of black holes and the coevolution of black holes and galaxies. Here we report the discovery of an ultraluminous quasar, SDSS J010013.02+280225.8, at redshift z = 6.30. It has an optical and near-infrared luminosity a few times greater than those of previously known z > 6 quasars. On the basis of the deep absorption trough on the blue side of the Lyman-α emission line in the spectrum, we estimate the proper size of the ionized proximity zone associated with the quasar to be about 26 million light years, larger than found with other z > 6.1 quasars with lower luminosities. We estimate (on the basis of a near-infrared spectrum) that the black hole has a mass of ∼1.2 × 1010, which is consistent with the 1.3 × 1010 derived by assuming an Eddington-limited accretion rate.

An extremely high-altitude plume seen at Mars’ morning terminator

Nature 518, 7540 (2015). doi:10.1038/nature14162

Authors: A. Sánchez-Lavega, A. García Muñoz, E. García-Melendo, S. Pérez-Hoyos, J. M. Gómez-Forrellad, C. Pellier, M. Delcroix, M. A. López-Valverde, F. González-Galindo, W. Jaeschke, D. Parker, J. Phillips & D. Peach

The Martian limb (that is, the observed ‘edge’ of the planet) represents a unique window into the complex atmospheric phenomena occurring there. Clouds of ice crystals (CO2 ice or H2O ice) have been observed numerous times by spacecraft and ground-based telescopes, showing that clouds are typically layered and always confined below an altitude of 100 kilometres; suspended dust has also been detected at altitudes up to 60 kilometres during major dust storms. Highly concentrated and localized patches of auroral emission controlled by magnetic field anomalies in the crust have been observed at an altitude of 130 kilometres. Here we report the occurrence in March and April 2012 of two bright, extremely high-altitude plumes at the Martian terminator (the day–night boundary) at 200 to 250 kilometres or more above the surface, and thus well into the ionosphere and the exosphere. They were spotted at a longitude of about 195° west, a latitude of about −45° (at Terra Cimmeria), extended about 500 to 1,000 kilometres in both the north–south and east–west directions, and lasted for about 10 days. The features exhibited day-to-day variability, and were seen at the morning terminator but not at the evening limb, which indicates rapid evolution in less than 10 hours and a cyclic behaviour. We used photometric measurements to explore two possible scenarios and investigate their nature. For particles reflecting solar radiation, clouds of CO2-ice or H2O-ice particles with an effective radius of 0.1 micrometres are favoured over dust. Alternatively, the plume could arise from auroral emission, of a brightness more than 1,000 times that of the Earth’s aurora, over a region with a strong magnetic anomaly where aurorae have previously been detected. Importantly, both explanations defy our current understanding of Mars’ upper atmosphere.

Reaching 12 billion times the mass of the sun just a billion years after the big bang, a black hole has astronomers mystified about its rapid growth