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Io Volcanism Seen by New Horizons: A Major Eruption of the Tvashtar Volcano
Stern, S. A.; Weaver, H. A.; Spencer, J. R. +14 more
Jupiter’s moon Io is known to host active volcanoes. In February and March 2007, the New Horizons spacecraft obtained a global snapshot of Io’s volcanism. A 350-kilometer-high volcanic plume was seen to emanate from the Tvashtar volcano (62°N, 122°W), and its motion was observed. The plume’s morphology and dynamics support nonballistic models of l…
Enceladus: Cosmic Graffiti Artist Caught in the Act
Verbiscer, Anne; Helfenstein, Paul; Showalter, Mark +1 more
As one of the most geologically active bodies in the solar system, Saturn's moon Enceladus not only coats itself with water ice particles, it accounts for the unusually high albedos of the other satellites orbiting within Saturn's vast, tenuous E ring. This effect is evident in Hubble Space Telescope observations obtained at true opposition on 13 …
Io’s Atmospheric Response to Eclipse: UV Aurorae Observations
Stern, S. A.; Saur, J.; Strobel, D. F. +18 more
The New Horizons (NH) spacecraft observed Io’s aurora in eclipse on four occasions during spring 2007. NH Alice ultraviolet spectroscopy and concurrent Hubble Space Telescope ultraviolet imaging in eclipse investigate the relative contribution of volcanoes to Io’s atmosphere and its interaction with Jupiter’s magnetosphere. Auroral brightness and …
Locating the Two Black Holes in NGC 6240
Canalizo, Gabriela; Max, Claire E.; de Vries, Willem H.
Mergers play an important role in galaxy evolution and are key to understanding the correlation between central black hole mass and host-galaxy properties. We used the new technology of adaptive optics at the Keck II telescope to observe NGC 6240, a merger between two disk galaxies. Our high-resolution near-infrared images, combined with radio and…
Jupiter’s Nightside Airglow and Aurora
Parker, Joel Wm.; Stern, S. Alan; Weaver, Harold A. +12 more
Observations of Jupiter’s nightside airglow (nightglow) and aurora obtained during the flyby of the New Horizons spacecraft show an unexpected lack of ultraviolet nightglow emissions, in contrast to the case during the Voyager flybys in 1979. The flux and average energy of precipitating electrons generally decrease with increasing local time acros…