Search Publications
A binary origin for `blue stragglers' in globular clusters
Sills, Alison; Knigge, Christian; Leigh, Nathan
Blue stragglers in globular clusters are abnormally massive stars that should have evolved off the stellar main sequence long ago. There are two known processes that can create these objects: direct stellar collisions and binary evolution. However, the relative importance of these processes has remained unclear. In particular, the total number of …
The changing phases of extrasolar planet CoRoT-1b
de Mooij, Ernst J. W.; Albrecht, Simon; Snellen, Ignas A. G.
Hot Jupiters are a class of extrasolar planet that orbit their parent stars at very short distances. They are expected to be tidally locked, which can lead to a large temperature difference between their daysides and nightsides. Infrared observations of eclipsing systems have yielded dayside temperatures for a number of transiting planets. The day…
Saturn's rotation period from its atmospheric planetary-wave configuration
Read, P. L.; Dowling, T. E.; Schubert, G.
The rotation period of a gas giant's magnetic field (called the System III reference frame) is commonly used to infer its bulk rotation. Saturn's dipole magnetic field is not tilted relative to its rotation axis (unlike Jupiter, Uranus and Neptune), so the surrogate measure of its long-wavelength (kilometric) radiation is currently used to fix the…
A single sub-kilometre Kuiper belt object from a stellar occultation in archival data
Zucker, S.; Gal-Yam, A.; Sari, R. +5 more
The Kuiper belt is a remnant of the primordial Solar System. Measurements of its size distribution constrain its accretion and collisional history, and the importance of material strength of Kuiper belt objects. Small, sub-kilometre-sized, Kuiper belt objects elude direct detection, but the signature of their occultations of background stars shoul…
Global circulation as the main source of cloud activity on Titan
Sotin, Christophe; Barnes, Jason W.; Le Mouélic, Stéphane +11 more
Clouds on Titan result from the condensation of methane and ethane and, as on other planets, are primarily structured by circulation of the atmosphere. At present, cloud activity mainly occurs in the southern (summer) hemisphere, arising near the pole and at mid-latitudes from cumulus updrafts triggered by surface heating and/or local methane sour…
Storms in the tropics of Titan
Brown, M. E.; Schaller, E. L.; Roe, H. G. +1 more
Methane clouds, lakes and most fluvial features on Saturn's moon Titan have been observed in the moist high latitudes, while the tropics have been nearly devoid of convective clouds and have shown an abundance of wind-carved surface features like dunes. The presence of small-scale channels and dry riverbeds near the equator observed by the Huygens…
No sodium in the vapour plumes of Enceladus
Johnson, Robert E.; Dougherty, Michele K.; Schneider, Nicholas M. +5 more
The discovery of water vapour and ice particles erupting from Saturn's moon Enceladus fuelled speculation that an internal ocean was the source. Alternatively, the source might be ice warmed, melted or crushed by tectonic motions. Sodium chloride (that is, salt) is expected to be present in a long-lived ocean in contact with a rocky core. Here we …
The first decade of science with Chandra and XMM-Newton
Weisskopf, Martin C.; Schartel, Norbert; Santos-Lleo, Maria +2 more
NASA's Chandra X-ray Observatory and the ESA's X-ray Multi-Mirror Mission (XMM-Newton) made their first observations ten years ago. The complementary capabilities of these observatories allow us to make high-resolution images and precisely measure the energy of cosmic X-rays. Less than 50years after the first detection of an extrasolar X-ray sourc…
Planetary science: Enceladus with a grain of salt
Spencer, John
The observation that water plumes erupt from cracks on Saturn's moon Enceladus has fired speculation about a possible subsurface ocean. The latest searches for sodium salts point to the existence of such an ocean.