Search Publications
Spectroscopic identification of water emission from a main-belt comet
Villanueva, Geronimo L.; Bodewits, Dennis; Hsieh, Henry H. +4 more
Main-belt comets are small Solar System bodies located in the asteroid belt that repeatedly exhibit comet-like activity (that is, dust comae or tails) during their perihelion passages, strongly indicating ice sublimation1,2. Although the existence of main-belt comets implies the presence of extant water ice in the asteroid belt, no gas …
15NH3 in the atmosphere of a cool brown dwarf
Henning, Thomas; Östlin, Göran; Colina, Luis +40 more
Brown dwarfs serve as ideal laboratories for studying the atmospheres of giant exoplanets on wide orbits, as the governing physical and chemical processes within them are nearly identical1,2. Understanding the formation of gas-giant planets is challenging, often involving the endeavour to link atmospheric abundance ratios, such as the c…
A super-massive Neptune-sized planet
Schlieder, Joshua E.; Howell, Steve B.; Cubillos, Patricio E. +54 more
Neptune-sized planets exhibit a wide range of compositions and densities, depending on factors related to their formation and evolution history, such as the distance from their host stars and atmospheric escape processes. They can vary from relatively low-density planets with thick hydrogen-helium atmospheres1,2 to higher-density planet…
Resolved imaging confirms a radiation belt around an ultracool dwarf
Kao, Melodie M.; Shkolnik, Evgenya L.; Mioduszewski, Amy J. +1 more
Radiation belts are present in all large-scale Solar System planetary magnetospheres: Earth, Jupiter, Saturn, Uranus and Neptune1. These persistent equatorial zones of relativistic particles up to tens of megaelectron volts in energy can extend further than ten times the planet's radius, emit gradually varying radio emissions2-4
X-ray polarization evidence for a 200-year-old flare of Sgr A*
Ingram, Adam; Kaaret, Philip; Wu, Kinwah +101 more
The centre of the Milky Way Galaxy hosts a black hole with a solar mass of about 4 million (Sagittarius A* (Sgr A)) that is very quiescent at present with a luminosity many orders of magnitude below those of active galactic nuclei1. Reflection of X-rays from Sgr A* by dense gas in the Galactic Centre region offers …
A shared accretion instability for black holes and neutron stars
Altamirano, D.; Belloni, T.; Degenaar, N. +20 more
Accretion disks around compact objects are expected to enter an unstable phase at high luminosity1. One instability may occur when the radiation pressure generated by accretion modifies the disk viscosity, resulting in the cyclic depletion and refilling of the inner disk on short timescales2. Such a scenario, however, has onl…
An evolutionary continuum from nucleated dwarf galaxies to star clusters
Zhang, Hongxin; Liu, Chengze; Cuillandre, Jean-Charles +21 more
Systematic studies1-4 have revealed hundreds of ultra-compact dwarf galaxies (UCDs5) in the nearby Universe. With half-light radii rh of approximately 10-100 parsecs and stellar masses M* ≈ 106-108 solar masses, UCDs are among the densest known stellar systems6. Although …
Minutes-duration optical flares with supernova luminosities
Filippenko, Alexei V.; de Boer, Thomas; Magnier, Eugene A. +74 more
In recent years, certain luminous extragalactic optical transients have been observed to last only a few days1. Their short observed duration implies a different powering mechanism from the most common luminous extragalactic transients (supernovae), whose timescale is weeks2. Some short-duration transients, most notably AT201…
A high-mass X-ray binary descended from an ultra-stripped supernova
Gies, Douglas R.; Richardson, Noel D.; Younes, George +6 more
Ultra-stripped supernovae are different from other terminal explosions of massive stars, as they show little or no ejecta from the actual supernova event1,2. They are thought to occur in massive binary systems after the exploding star has lost its surface through interactions with its companion2. Such supernovae produce littl…
A rotating white dwarf shows different compositions on its opposite faces
Kulkarni, S. R.; Vennes, Stéphane; Hermes, J. J. +35 more
White dwarfs, the extremely dense remnants left behind by most stars after their death, are characterized by a mass comparable to that of the Sun compressed into the size of an Earth-like planet. In the resulting strong gravity, heavy elements sink towards the centre and the upper layer of the atmosphere contains only the lightest element present,…