Atmospheric confinement of jet streams on Uranus and Neptune
Nature 497, 7449 (2013). doi:10.1038/nature12131
Authors: Yohai Kaspi, Adam P. Showman, William B. Hubbard, Oded Aharonson & Ravit Helled
The observed cloud-level atmospheric circulation on the outer planets of the Solar System is dominated by strong east–west jet streams. The depth of these winds is a crucial unknown in constraining their overall dynamics, energetics and internal structures. There are two approaches to explaining the existence of these strong winds. The first suggests that the jets are driven by shallow atmospheric processes near the surface, whereas the second suggests that the atmospheric dynamics extend deeply into the planetary interiors. Here we report that on Uranus and Neptune the depth of the atmospheric dynamics can be revealed by the planets’ respective gravity fields. We show that the measured fourth-order gravity harmonic, J4, constrains the dynamics to the outermost 0.15 per cent of the total mass of Uranus and the outermost 0.2 per cent of the total mass of Neptune. This provides a stronger limit to the depth of the dynamical atmosphere than previously suggested, and shows that the dynamics are confined to a thin weather layer no more than about 1,000 kilometres deep on both planets.
Planetary science: Plumbing the depths of Uranus and Neptune
Nature 497, 7449 (2013). doi:10.1038/497323a
Authors: Peter Read
An analysis of data collected by the Voyager 2 spacecraft and by ground-based telescopes limits the depths to which winds penetrate into Uranus and Neptune, informing the debate about these planets' internal structures. See Letter p.344
Astronomy: Japan's work on ALMA telescope
Nature 497, 7449 (2013). doi:10.1038/497317e
Authors: Masahiko Hayashi & Satoru Iguchi
Your report on the Atacama Large Millimeter/submillimeter Array (ALMA), the world's highest-altitude radio telescope, omits mention of Japan's contribution (Nature495, 156–159; 201310.1038/495156a).The National Astronomical Observatory of Japan (NAOJ) is one of three executive partners of ALMA
Magnetar found at giant black hole
Nature 497, 7449 (2013). http://www.nature.com/doifinder/10.1038/497296a
Author: Eugenie Samuel Reich
Magnetized neutron star could test Einstein’s theory.
Deep inside the Hyades star cluster, a pair of burned-out stars are yielding clues to the presence of rocky planets that may have whirled around them. Asteroid debris is 'raining' into the hot atmospheres of these white dwarfs. Asteroids should consist of the same material that form terrestrial planets, and seeing evidence of asteroids points to the possibility of Earth-sized planets in the same system.
(author unknown)