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Optical Images of an Exosolar Planet 25 Light-Years from Earth
Kalas, Paul; Fitzgerald, Michael P.; Graham, James R. +6 more
Fomalhaut, a bright star 7.7 parsecs (25 light-years) from Earth, harbors a belt of cold dust with a structure consistent with gravitational sculpting by an orbiting planet. Here, we present optical observations of an exoplanet candidate, Fomalhaut b. Fomalhaut b lies about 119 astronomical units (AU) from the star and 18 AU of the dust belt, matc…
CoRoT Measures Solar-Like Oscillations and Granulation in Stars Hotter Than the Sun
Neiner, Coralie; Baudin, Frédéric; Aerts, Conny +41 more
Oscillations of the Sun have been used to understand its interior structure. The extension of similar studies to more distant stars has raised many difficulties despite the strong efforts of the international community over the past decades. The CoRoT (Convection Rotation and Planetary Transits) satellite, launched in December 2006, has now measur…
Polarized Gamma-Ray Emission from the Crab
Hill, A. B.; Bird, A. J.; Ubertini, P. +7 more
Pulsar systems accelerate particles to immense energies. The detailed functioning of these engines is still poorly understood, but polarization measurements of high-energy radiation may allow us to locate where the particles are accelerated. We have detected polarized gamma rays from the vicinity of the Crab pulsar using data from the spectrometer…
Titan’s Rotation Reveals an Internal Ocean and Changing Zonal Winds
Iess, Luciano; Stiles, Bryan W.; Kirk, Randolph L. +6 more
Cassini radar observations of Saturn’s moon Titan over several years show that its rotational period is changing and is different from its orbital period. The present-day rotation period difference from synchronous spin leads to a shift of ~0.36° per year in apparent longitude and is consistent with seasonal exchange of angular momentum between th…
Million-Degree Plasma Pervading the Extended Orion Nebula
Skinner, Stephen L.; Güdel, Manuel; Rebull, Luisa +3 more
Most stars form as members of large associations within dense, very cold (10 to 100 kelvin) molecular clouds. The nearby giant molecular cloud in Orion hosts several thousand stars of ages less than a few million years, many of which are located in or around the famous Orion Nebula, a prominent gas structure illuminated and ionized by a small grou…
The Fermi Gamma-Ray Space Telescope Discovers the Pulsar in the Young Galactic Supernova Remnant CTA 1
Ozaki, M.; Caraveo, P. A.; Orlando, E. +182 more
Energetic young pulsars and expanding blast waves [supernova remnants (SNRs)] are the most visible remains after massive stars, ending their lives, explode in core-collapse supernovae. The Fermi Gamma-Ray Space Telescope has unveiled a radio quiet pulsar located near the center of the compact synchrotron nebula inside the supernova remnant CTA 1. …
Temperature and Composition of Saturn’s Polar Hot Spots and Hexagon
Fletcher, L. N.; Irwin, P. G. J.; Teanby, N. A. +11 more
Saturn’s poles exhibit an unexpected symmetry in hot, cyclonic polar vortices, despite huge seasonal differences in solar flux. The cores of both vortices are depleted in phosphine gas, probably resulting from subsidence of air into the troposphere. The warm cores are present throughout the upper troposphere and stratosphere at both poles. The the…
The Dust Halo of Saturn’s Largest Icy Moon, Rhea
Coates, A. J.; Krupp, N.; Woch, J. +32 more
Saturn’s moon Rhea had been considered massive enough to retain a thin, externally generated atmosphere capable of locally affecting Saturn’s magnetosphere. The Cassini spacecraft’s in situ observations reveal that energetic electrons are depleted in the moon’s vicinity. The absence of a substantial exosphere implies that Rhea’s magnetospheric int…
Dynamics of Saturn's South Polar Vortex
Fletcher, Leigh N.; West, Robert A.; Porco, Carolyn C. +9 more
We present observations of Saturn's south polar vortex (SPV) showing that it shares some properties with terrestrial hurricanes: cyclonic circulation, warm central region (the eye) surrounded by a ring of high clouds (the eye wall), and convective clouds outside the eye. The polar location and the absence of an ocean are major differences. It also…