Search Publications
Long γ-ray bursts and core-collapse supernovae have different environments
Pian, E.; Ferguson, H. C.; Gull, T. R. +30 more
When massive stars exhaust their fuel, they collapse and often produce the extraordinarily bright explosions known as core-collapse supernovae. On occasion, this stellar collapse also powers an even more brilliant relativistic explosion known as a long-duration γ-ray burst. One would then expect that these long γ-ray bursts and core-collapse super…
Radioactive 26Al from massive stars in the Galaxy
Wang, Wei; Knödlseder, Jürgen; Winkler, Christoph +13 more
Gamma-rays from radioactive 26Al (half-life ~7.2 × 105years) provide a `snapshot' view of continuing nucleosynthesis in the Galaxy. The Galaxy is relatively transparent to such γ-rays, and emission has been found concentrated along its plane. This led to the conclusion that massive stars throughout the Galaxy dominate the pro…
A novel explosive process is required for the γ-ray burst GRB 060614
Sharon, K.; Cenko, S. B.; Peterson, B. A. +23 more
Over the past decade, our physical understanding of γ-ray bursts (GRBs) has progressed rapidly, thanks to the discovery and observation of their long-lived afterglow emission. Long-duration (>~2s) GRBs are associated with the explosive deaths of massive stars (`collapsars', ref. 1), which produce accompanying supernovae; the short-duration (<…
Episodic outgassing as the origin of atmospheric methane on Titan
Sotin, Christophe; Lunine, Jonathan I.; Tobie, Gabriel
Saturn's largest satellite, Titan, has a massive nitrogen atmosphere containing up to 5 per cent methane near its surface. Photochemistry in the stratosphere would remove the present-day atmospheric methane in a few tens of millions of years. Before the Cassini-Huygens mission arrived at Saturn, widespread liquid methane or mixed hydrocarbon seas …
A magnetic reconnection X-line extending more than 390 Earth radii in the solar wind
Balogh, A.; McComas, D. J.; Reme, H. +8 more
Magnetic reconnection in a current sheet converts magnetic energy into particle energy, a process that is important in many laboratory, space and astrophysical contexts. It is not known at present whether reconnection is fundamentally a process that can occur over an extended region in space or whether it is patchy and unpredictable in nature. Fre…
Variations in solar luminosity and their effect on the Earth's climate
Fröhlich, C.; Foukal, P.; Spruit, H. +1 more
Variations in the Sun's total energy output (luminosity) are caused by changing dark (sunspot) and bright structures on the solar disk during the 11-year sunspot cycle. The variations measured from spacecraft since 1978 are too small to have contributed appreciably to accelerated global warming over the past 30 years. In this Review, we show that …
Methane drizzle on Titan
Neubauer, Fritz M.; McKay, Christopher P.; Tokano, Tetsuya +4 more
Saturn's moon Titan shows landscapes with fluvial features suggestive of hydrology based on liquid methane. Recent efforts in understanding Titan's methane hydrological cycle have focused on occasional cloud outbursts near the south pole or cloud streaks at southern mid-latitudes and the mechanisms of their formation. It is not known, however, if …
Stabilization of the disk around βPictoris by extremely carbon-rich gas
Weinberger, Alycia J.; Roberge, Aki; Feldman, Paul D. +2 more
The edge-on disk surrounding the nearby young star βPictoris is the archetype of `debris disks', which are composed of dust and gas produced by collisions between-and evaporation of-planetesimals, analogues of Solar System comets and asteroids. These disks may provide insight into the formation and early evolution of terrestrial planets. Previous …
Discovery of two new satellites of Pluto
Stern, S. A.; Weaver, H. A.; Mutchler, M. J. +6 more
Pluto's first known satellite, Charon, was discovered in 1978. It has a diameter (~1,200km) about half that of Pluto, which makes it larger, relative to its primary, than any other moon in the Solar System. Previous searches for other satellites around Pluto have been unsuccessful, but they were not sensitive to objects <~150km in diameter and …
Diapir-induced reorientation of Saturn's moon Enceladus
Nimmo, Francis; Pappalardo, Robert T.
Enceladus is a small icy satellite of Saturn. Its south polar region consists of young, tectonically deformed terrain and has an anomalously high heat flux. This heat flux is probably due to localized tidal dissipation within either the ice shell or the underlying silicate core. The surface deformation is plausibly due to upwelling of low-density …