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The aurorae of Uranus past equinox
Lamy, L.; Badman, S. V.; Cowley, S. W. H. +9 more
The aurorae of Uranus were recently detected in the far ultraviolet with the Hubble Space Telescope (HST) providing a new, so far unique, means to remotely study the asymmetric Uranian magnetosphere from Earth. We analyze here two new HST Uranus campaigns executed in September 2012 and November 2014 with different temporal coverage and under varia…
Constraints on Io's interior from auroral spot oscillations
Saur, Joachim; Roth, Lorenz; Feldman, Paul D. +3 more
The morphology of Io's aurora is dominated by bright spots near the equator that oscillate up and down in approximate correlation with the oscillating orientation of the Jovian magnetospheric field. Analyzing Hubble Space Telescope images, we find that the auroral spots oscillate in phase with the time-variable Jovian magnetic field at Io and that…
Seasonal Changes in Hydrogen Escape From Mars Through Analysis of HST Observations of the Martian Exosphere Near Perihelion
Villanueva, G. L.; Bertaux, J. L.; Clarke, J. T. +5 more
Hubble Space Telescope (HST) observations of the Martian hydrogen exosphere in Lyman α are presented in this paper for a period when Mars passed perihelion and southern summer solstice in its orbit. The peak intensity in the exospheric Lyman α brightness was recorded after Mars went past its perihelion, slightly after southern summer solstice. The…
IUVS echelle-mode observations of interplanetary hydrogen: Standard for calibration and reference for cavity variations between Earth and Mars during MAVEN cruise
Bertaux, Jean-Loup; Chaufray, Jean-Yves; Stewart, Ian +11 more
The high-resolution echelle mode of the Imaging Ultraviolet Spectrograph (IUVS) instrument on the Mars Atmosphere and Volatile Evolution mission has been designed to measure D and H Lyman α emissions from the Martian atmosphere to obtain key information about the physical processes by which water escapes into space. Toward this goal, the absolute …
Long-Term Variability of Jupiter's Magnetodisk and Implications for the Aurora
Bunce, Emma J.; Clarke, John T.; Vogt, Marissa F. +2 more
Observations of Jupiter's UV auroral emissions collected over several years show that the ionospheric positions of the main emission and the Ganymede footprint can vary by as much as 3° in latitude. One explanation for this shift is a change of Jupiter's current sheet current density, which would alter the amount of field line stretching and displ…
Morphology of Ganymede's FUV auroral ovals
Saur, Joachim; Roth, Lorenz; Feldman, Paul D. +4 more
We study the morphology of Ganymede's FUV aurora by analyzing spectral images obtained over the past two decades by the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope. The observations cover the eastern and western elongation as well as various magnetic latitudes of Ganymede within the Jovian plasma sheet. We find both as…
An isolated, bright cusp aurora at Saturn
Baines, K. H.; Dougherty, M. K.; Gray, R. L. +16 more
Saturn's dayside aurora displays a number of morphological features poleward of the main emission region. We present an unusual morphology captured by the Hubble Space Telescope on 14 June 2014 (day 165), where for 2 h, Saturn's FUV aurora faded almost entirely, with the exception of a distinct emission spot at high latitude. The spot remained fix…
Characterization of Jupiter's secondary auroral oval and its response to hot plasma injections
Woodfield, E. E.; Gray, R. L.; Badman, S. V. +1 more
We present Jovian auroral observations from the 2014 January Hubble Space Telescope (HST) campaign and characterize the auroral second oval feature with particular attention to the response to hot plasma injections. The location of the second oval feature lies between the Ganymede and Europa moon footprint contours between 150 and 240° system III …