Search Publications
The determination of the structure of Saturn's F ring by nearby moonlets
Charnoz, Sébastien; Murray, Carl D.; Beurle, Kevin +3 more
Saturn's narrow F ring exhibits several unusual features that vary on timescales of hours to years. These include transient clumps, a central core surrounded by a multistranded structure and a regular series of longitudinal channels associated with Prometheus, one of the ring's two `shepherding' satellites. Several smaller moonlets and clumps have…
Flares from a candidate Galactic magnetar suggest a missing link to dim isolated neutron stars
Hanlon, L.; McBreen, B.; Bremer, M. +39 more
Magnetars are young neutron stars with very strong magnetic fields of the order of 1014-1015G. They are detected in our Galaxy either as soft γ-ray repeaters or anomalous X-ray pulsars. Soft γ-ray repeaters are a rare type of γ-ray transient sources that are occasionally detected as bursters in the high-energy sky. No optical…
Jovian-like aurorae on Saturn
Bunce, Emma J.; Melin, Henrik; Miller, Steve +5 more
Planetary aurorae are formed by energetic charged particles streaming along the planet's magnetic field lines into the upper atmosphere from the surrounding space environment. Earth's main auroral oval is formed through interactions with the solar wind, whereas that at Jupiter is formed through interactions with plasma from the moon Io inside its …
Complex structure within Saturn's infrared aurora
Drossart, Pierre; Dougherty, Michele K.; Bunce, Emma J. +14 more
The majority of planetary aurorae are produced by electrical currents flowing between the ionosphere and the magnetosphere which accelerate energetic charged particles that hit the upper atmosphere. At Saturn, these processes collisionally excite hydrogen, causing ultraviolet emission, and ionize the hydrogen, leading to H3+ …
The lakes of Titan
Lorenz, R. D.; Stiles, B.; Kelleher, K. +35 more
The surface of Saturn's haze-shrouded moon Titan has long been proposed to have oceans or lakes, on the basis of the stability of liquid methane at the surface. Initial visible and radar imaging failed to find any evidence of an ocean, although abundant evidence was found that flowing liquids have existed on the surface. Here we provide definitive…
Extremely fast acceleration of cosmic rays in a supernova remnant
Maeda, Yoshitomo; Takahashi, Tadayuki; Uchiyama, Yasunobu +2 more
Galactic cosmic rays (CRs) are widely believed to be accelerated by shock waves associated with the expansion of supernova ejecta into the interstellar medium. A key issue in this long-standing conjecture is a theoretical prediction that the interstellar magnetic field can be substantially amplified at the shock of a young supernova remnant (SNR) …
Dark matter maps reveal cosmic scaffolding
Refregier, Alexandre; Ellis, Richard; Mobasher, Bahram +17 more
Ordinary baryonic particles (such as protons and neutrons) account for only one-sixth of the total matter in the Universe. The remainder is a mysterious `dark matter' component, which does not interact via electromagnetism and thus neither emits nor reflects light. As dark matter cannot be seen directly using traditional observations, very little …
A black hole in a globular cluster
Kundu, Arunav; Zepf, Stephen E.; Maccarone, Thomas J. +1 more
Globular star clusters contain thousands to millions of old stars packed within a region only tens of light years across. Their high stellar densities make it very probable that their member stars will interact or collide. There has accordingly been considerable debate about whether black holes should exist in these star clusters. Some theoretical…
Shear heating as the origin of the plumes and heat flux on Enceladus
Spencer, J. R.; Nimmo, F.; Pappalardo, R. T. +1 more
Enceladus, a small icy satellite of Saturn, has active plumes jetting from localized fractures (`tiger stripes') within an area of high heat flux near the south pole. The plume characteristics and local high heat flux have been ascribed either to the presence of liquid water within a few tens of metres of the surface, or the decomposition of clath…
Early geochemical environment of Mars as determined from thermodynamics of phyllosilicates
Bibring, Jean-Pierre; Poulet, Francois; Chevrier, Vincent
Images of geomorphological features that seem to have been produced by the action of liquid water have been considered evidence for wet surface conditions on early Mars. Moreover, the recent identification of large deposits of phyllosilicates, associated with the ancient Noachian terrains suggests long-timescale weathering of the primary basaltic …