Search Publications
Planet-Wide Ozone Destruction in the Middle Atmosphere on Mars During Global Dust Storm
Aoki, S.; Vandaele, A. C.; Daerden, F. +22 more
The Nadir and Occultation for MArs Discovery (NOMAD)/UV-visible (UVIS) spectrometer on the ExoMars Trace Gas Orbiter provided observations of ozone (O3) and water vapor in the global dust storm of 2018. Here we show in detail, using advanced data filtering and chemical modeling, how Martian O3 in the middle atmosphere was des…
A Revised Understanding of the Structure of the Venusian Magnetotail From a High-Altitude Intercept With a Tail Ray by Parker Solar Probe
Collinson, Glyn A.; Ramstad, Robin; Frahm, Rudy +5 more
One of the major discoveries of NASA's 1979-1991 Pioneer Venus Orbiter is that the nightside ionosphere becomes filamentary at high altitude, forming comet-like tail rays. Pioneer Venus Orbiter could not establish how much farther into the wake of Venus tail rays extend, nor understand how they form. Here we present plasma and fields data from the…
Alternating North-South Brightness Ratio of Ganymede's Auroral Ovals: Hubble Space Telescope Observations Around the Juno PJ34 Flyby
Saur, Joachim; Roth, Lorenz; Strobel, Darrell F. +17 more
We report results of Hubble Space Telescope observations from Ganymede's orbitally trailing side which were taken around the flyby of the Juno spacecraft on 7 June 2021. We find that Ganymede's northern and southern auroral ovals alternate in brightness such that the oval facing Jupiter's magnetospheric plasma sheet is brighter than the other one.…
Variations in Vertical CO/CO2 Profiles in the Martian Mesosphere and Lower Thermosphere Measured by the ExoMars TGO/NOMAD: Implications of Variations in Eddy Diffusion Coefficient
Vandaele, Ann Carine; Modak, Ashimananda; Brines, Adrian +19 more
Using the Nadir and Occultation for MArs Discovery instrument aboard Trace Gas Orbiter, we derived the CO/CO2 profiles between 75 and 105 km altitude with the equivalent width technique. The derived CO/CO2 profiles showed significant seasonal variations in the southern hemisphere with decreases near perihelion and increases n…
Jupiter's X-Ray and UV Dark Polar Region
Jackman, C. M.; Johnson, R. E.; Branduardi-Raymont, G. +16 more
We present 14 simultaneous Chandra X-ray Observatory (CXO)-Hubble Space Telescope (HST) observations of Jupiter's Northern X-ray and ultraviolet (UV) aurorae from 2016 to 2019. Despite the variety of dynamic UV and X-ray auroral structures, one region is conspicuous by its persistent absence of emission: the dark polar region (DPR). Previous HST o…
Evidence of Alfvén Waves Generated by Mode Coupling in the Magnetotail Lobe
Zhang, Tielong; Sun, Jicheng; Wang, Guoqiang +2 more
Mode coupling is an important mechanism to excite Alfvén waves and has been extensively investigated based on numerical simulations. However, no direct observational evidence has been found regarding to this mechanism in the magnetotail lobe. Here, we report an in-situ observation that an Alfvén wave with a period of several minutes is clearly rel…
Tracking the Evolution of an Ocean Within Mimas Using the Herschel Impact Basin
Rhoden, A. R.; Denton, C. A.
Mimas' small size, lack of geologic activity, and high eccentricity suggest a frozen, inactive history. However, Cassini libration measurements are best explained by a present-day liquid ocean under an ice shell 24-31 km thick, a configuration that tidal heating can support. These unexpected findings have motivated further study of Mimas' surface …
BepiColombo Mio Observations of Low-Energy Ions During the First Mercury Flyby: Initial Results
Persson, Moa; Saito, Yoshifumi; Delcourt, Dominique +14 more
We present initial results of low-energy ion observations from BepiColombo's first Mercury flyby. Unprecedentedly high time resolution measurements of low energy ions at Mercury by BepiColombo Mio reveal rapid (a few seconds) and large (1-2 orders of magnitude) fluctuations of ion flux around the magnetopause and within the magnetosphere. Around t…
Paleolake Inlet Valley Formation: Factors Controlling Which Craters Breached on Early Mars
Fassett, C. I.; Bamber, Emily R.; Goudge, T. A. +2 more
The ancient surface of Mars is dominated by degraded impact craters with reduced or eliminated rim relief. Some degraded craters have an inlet valley, while many remain fluvially isolated. Despite controlling Martian fluvial connectivity, few constraints exist on why some—but not all—degraded craters possess inlets. We compared a suite of properti…
Saturn Anomalous Myriametric Radiation, a New Type of Saturn Radio Emission Revealed by Cassini
Jackman, C. M.; Kurth, W. S.; Cecconi, B. +10 more
A new radio component namely Saturn Anomalous Myriametric Radiation (SAM) is reported. A total of 193 SAM events have been identified by using all the Cassini Saturn orbital data. SAM emissions are L-O mode radio emission and occasionally accompanied by a first harmonic in R-X mode. SAM's intensities decrease with increasing distance from Saturn, …