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Abstract:

We present a calibrated catalog of Cassini Visible and Infrared Mapping Spectrometer (VIMS) observations of Jupiter, together with the processing workflow used to generate the final publicly available products. Starting from the raw VIMS cubes, the workflow produces radiometrically consistent multiextension Flexible Image Transport System files and includes a revised visible-channel calibration, a revised infrared-channel calibration that resolves a subset of problematic cases not satisfactorily treated by the standard Integrated Software for Imagers and Spectrometers pipeline, corrections for pointing-related misalignments between spectral cubes and geometric backplanes, and customized dark signal correction strategies. The final products include calibrated spectral cubes together with geometry backplanes and wavelength information for subsequent scientific analysis. We assess the consistency of the calibrated products through internal validation tests and comparisons with independent reference spectra from the literature. The resulting products provide a uniform and validated data set of Cassini VIMS Jupiter observations for community use. The full catalog is available as a public dataset at doi:10.5281/zenodo.19223781.

Abstract:

Remote spectroscopy is used to characterize the mineralogy and infer the history of planetary bodies. Carbonaceous asteroids, such as B‐type (101955) Bennu, represent the earliest stages of planet formation. B types have a blue (negative) spectral slope and comprise <5% of asteroids. Samples from Bennu returned by the OSIRIS‐REx spacecraft complement remote observations of this rare population. We show here, using laboratory spectra that are directly comparable to spacecraft data, that OSIRIS‐REx accurately determined Bennu's dust content and most of its surface composition. However, spectra of the asteroid exhibit stronger water absorptions than those of bulk samples, possibly due to hydrous, Mg‐rich phosphate or solar wind implantation at Bennu's uppermost surface. Bennu samples spectrally resemble the most aqueously altered carbonaceous meteorites and samples of (162173) Ryugu, indicating similarly pervasive aqueous alteration. However, one carbon‐enriched Bennu stone does not appear to have a spectral analog among Ryugu samples or meteorites. Our findings demonstrate the leverage obtained using a wide range of wavelengths and that sample analysis anchors the interpretations of remote sensing, leading to more robust characterization of planetary surface composition and evolution.

Abstract:

The origin of the red colouration in Jupiter's Great Red Spot (GRS) is a long-standing question in planetary science. While several candidate chromophores have been proposed, no clear conclusions have been reached regarding its nature, evolution, or relationship to atmospheric dynamics. In this work, we perform microphysical simulations of the reddish haze over the GRS and quantify the production rates and timescales required to sustain it. Matching the previously reported chromophore column mass and effective radius in the GRS requires column-integrated injection fluxes in the range 1×10⁻¹²–7×10⁻¹² kg m⁻² s⁻¹, under low upwelling velocities in the upper troposphere (v<inf>trop</inf>≲1.5×10⁻⁴ m s⁻¹) and particle charges of at least 20 electrons/μm. Such rates exceed the mass flux that standard photochemical models of Jupiter currently supply via NH<inf>3</inf>–C<inf>2</inf>H<inf>2</inf> photochemistry at 0.1–0.2 bar, the most popular chromophore pathway in recent literature. We find a lower limit of 7 years on the haze formation time. We also assess commonly used size and vertical distribution parameterisations for the chromophore haze, finding that eddy diffusion prevents the long-term confinement of a thin layer and that the extinction is dominated by particles that can be represented by a single log-normal size distribution.

Abstract:

We report the first detection of stratospheric propadiene (CH₂CCH₂) and propene (C₃H₆) at Jupiter’s mid-to-high northern latitudes using IRTF-TEXES measurements recorded on March 5-6, 2025. Using radiative transfer software to quantitatively test for the presence of propadiene and propene, we report a >12-σ detection of propadiene and a >17-σ detection of propene at high latitudes inside Jupiter’s auroral region, where the species are most concentrated. For example, at 62 °N (planetocentric) inside Jupiter’s northern auroral region (henceforth ‘NAR’), we derive a 1-mbar propadiene abundance of 2.0 ± 0.2 ppbv, which is 40 ± 3 higher than abundances predicted by the Moses and Poppe (2017) photochemical model (henceforth ‘MP17’), and significantly higher than the 1.2-pbbv upper limit abundance derived at 42 °N (the lowest latitude sampled by the observations). Similarly, we derive a 1-mbar propene abundance 8.1 ± 0.5 ppbv at 62 °N inside Jupiter’s NAR, which is 28 ± 2 higher than the MP17 predicted abundance and significantly higher than the 6-ppbv 1-mbar upper limit abundance derived at 42 °N. The fact that propadiene and propene are most enriched inside Jupiter’s NAR strongly suggests that perturbations to the chemistry by auroral-related heating and exogenous ions/electrons are responsible for their significant enrichment, as has been observed for other unsaturated/aromatic hydrocarbon species. Spectral features of propane (C₃H₈) were not detected at any of the locations sampled by the data (poleward of 42 °N): 3-σ upper limits of ~10 ppbv at 10 mbar were derived at 62 °N inside Jupiter’s NAR, which is ~2.5 times the MP17 predicted abundance. The non-detection of propane could, in part, be explained by the vertical sensitivity of its mid-infrared emission lines to deeper pressures, where there is negligible auroral-related heating to warm the line forming region. The results of this work strongly advocate for development of ion-neutral chemistry models of Jupiter’s polar stratosphere to quantify how strong auroral-related heating and magnetospheric particles modify the reaction pathways that produce higher-order hydrocarbons.

Abstract:

Plain Language Summary: We present laboratory tests of a new instrument, the High‐resolution Volatiles and Minerals Moon Mapper ( H V M 3 ${\mathrm{H}\mathrm{V}\mathrm{M}}^{3}$ ). H V M 3 ${\mathrm{H}\mathrm{V}\mathrm{M}}^{3}$ will launch onboard the National Aeronautics and Space Administration's Lunar Trailblazer mission. It is an imaging spectrometer that will measure the spectrum of reflected sunlight in visible and infrared wavelengths for every pixel of an image. Scientists will interpret these spectra with the goal of measuring how water and ice are distributed across the lunar surface. Our laboratory tests indicate that the instrument is sensitive enough to measure small changes in the content of water on the lunar surface. We find the instrument capable of measuring areas of the Moon that are in permanent shadow using light reflected from neighboring surfaces like crater walls.