Search Publications
Water production activity of nine long-period comets from SOHO/SWAN observations of hydrogen Lyman-alpha: 2013-2016
Bertaux, J. -L.; Combi, M. R.; Quémerais, E. +4 more
Nine recently discovered long-period comets were observed by the Solar Wind Anisotropies (SWAN) Lyman-alpha all-sky camera on board the Solar and Heliosphere Observatory (SOHO) satellite during the period of 2013 to 2016. These were C/2012 K1 (PanSTARRS), C/2013 US10 (Catalina), C/2013 V5 (Oukaimeden), C/2013 R1 (Lovejoy), C/2014 E2 (Jacques), C/2…
Spatial variations in Titan's atmospheric temperature: ALMA and Cassini comparisons from 2012 to 2015
Irwin, P. G. J.; Achterberg, R. K.; Nixon, C. A. +7 more
Submillimeter emission lines of carbon monoxide (CO) in Titan's atmosphere provide excellent probes of atmospheric temperature due to the molecule's long chemical lifetime and stable, well constrained volume mixing ratio. Here we present the analysis of 4 datasets obtained with the Atacama Large Millimeter/Submillimeter Array (ALMA) in 2012, 2013,…
Spatial variations in the dust-to-gas ratio of Enceladus' plume
Nicholson, P. D.; Hansen, C. J.; Hedman, M. M. +4 more
On day 138 of 2010, the plume of dust and gas emerging from Enceladus' South Polar Terrain passed between the Sun and the Cassini spacecraft. This solar occultation enabled Cassini's Ultraviolet Imaging Spectrograph (UVIS) and the Visual and Infrared Mapping Spectrometer (VIMS) to obtain simultaneous measurements of the plume's gas and dust compon…
Mesospheric CO2 ice clouds on Mars observed by Planetary Fourier Spectrometer onboard Mars Express
Aoki, S.; Kasaba, Y.; Giuranna, M. +4 more
We have investigated mesospheric CO2 ice clouds on Mars through analysis of near-infrared spectra acquired by Planetary Fourier Spectrometer (PFS) onboard the Mars Express (MEx) from MY 27 to MY 32. With the highest spectral resolution achieved thus far in the relevant spectral range among remote-sensing experiments orbiting Mars, PFS e…
Mapping spiral waves and other radial features in Saturn's rings
Tiscareno, Matthew S.; Harris, Brent E.
We have analyzed the highest-quality images to be obtained by Cassini of Saturn's main rings after the Saturn Orbit Insertion (SOI) and before the Ring Grazing Orbits (RGO) and Grand Finale (GF). These images are comparable to those of SOI in fidelity, though not in nominal resolution, due to their high signal-to-noise. We have systematically sear…
Dusk/dawn atmospheric asymmetries on tidally-locked satellites: O2 at Europa
Leblanc, François; Johnson, Robert E.; Oza, Apurva V.
We use a simple analytic model to examine the effect of the atmospheric source properties on the spatial distribution of a volatile in a surface-bounded atmosphere on a satellite that is tidally-locked to its planet. Spatial asymmetries in the O2 exosphere of Europa observed using the Hubble Space Telescope appear to reveal on average a…
Asteroid thermal modeling in the presence of reflected sunlight
Myhrvold, Nathan
A new derivation of simple asteroid thermal models is presented, investigating the need to account correctly for Kirchhoff's law of thermal radiation when IR observations contain substantial reflected sunlight. The framework applies to both the NEATM and related thermal models. A new parameterization of these models eliminates the dependence of th…
An empirical examination of WISE/NEOWISE asteroid analysis and results
Myhrvold, Nathan
Asteroid observations by the WISE space telescope and the analysis of those observations by the NEOWISE project have provided more information about the diameter, albedo, and other properties of approximately 164,000 asteroids, more than all other sources combined. The raw data set from this mission will likely be the largest and most important su…
Improved estimation of Mars ionosphere total electron content
Sánchez-Cano, B.; Witasse, O.; Cantini, F. +5 more
We describe an improved method to estimate the Total Electron Content (TEC) of the Mars ionosphere from the echoes recorded by the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) (Picardi et al., 2005; Orosei et al., 2015) onboard Mars Express in its subsurface sounding mode. In particular, we demonstrate that this method solve…
A planetary-scale disturbance in a long living three vortex coupled system in Saturn's atmosphere
Hueso, R.; Sánchez-Lavega, A.; Rojas, J. F. +11 more
The zonal wind profile of Saturn has a unique structure at 60°N with a double-peaked jet that reaches maximum zonal velocities close to 100 ms-1. In this region, a singular group of vortices consisting of a cyclone surrounded by two anticyclones was active since 2012 until the time of this report. Our observation demonstrates that vorti…