Coloring Jupiter's clouds: Radiolysis of ammonium hydrosulfide (NH4SH)

Loeffler, M. J.; Hudson, R. L.

doi:10.1016/j.icarus.2017.10.041

Cited by 14 publications

(8 citation statements)

References 55 publications

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“…The brown color of the belts may be due to a deeper cloud deck possibly containing a sulfide, like NH 4 SH, as evoked by Owen and Terrile (1981). The color of the Great Red Spot (GRS), might be due to NH 3 photodissociation byproducts reacting with acetylene (C 2 H 2 ) at high altitude (Carlson et al, 2016), or irradiation of NH 4 SH particle (Loeffler and Hudson, 2018). In all cases, NH 3 seems to play a role in the cloud formation -and therefore, the colors in visible-light -of Jupiter.…”

Section: Introductionmentioning

confidence: 99%

Mapping of Jupiter’s tropospheric NH3 abundance using ground-based IRTF/TEXES observations at 5 µm

Blain

Fouchet

Greathouse

et al. 2018

Icarus

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We report on results of an observing campaign to support the Juno mission. At the beginning of 2016, using TEXES (Texas Echelon cross-dispersed Echelle Spectrograph), mounted on the NASA Infrared Telescope Facility (IRTF), we obtained data cubes of Jupiter in the 1930-1943 cm −1 spectral ranges (around 5 µm), which probe the atmosphere in the 1-4 bar region, with a spectral resolution of ≈ 0.15 cm −1 and an angular resolution of ≈ 1.4". This dataset is analysed by a code that combines a line-by-line radiative transfer model with a non-linear optimal estimation inversion method. The inversion retrieves the vertical abundance profiles of NH 3 -which is the main contributor at these wavelengthswith a maximum sensitivity at ≈ 1-3 bar, as well as the cloud transmittance. This retrieval is performed on more than one thousand pixels of our data cubes, producing maps of the disk, where all the major belts are visible. We present our retrieved NH 3 abundance maps which can be compared with the distribution observed by Juno's MWR Li et al., 2017) in the 2 bar region and discuss their significance for the understanding of Jupiter's atmospheric dynamics. We are able to show important latitudinal variations -such as in the North Equatorial Belt (NEB), where the NH 3 abundance is observed to drop down to 60 ppmv at 2 bar -as well as longitudinal variability. In the zones, we find the NH 3 abundance to increase with depth, from 100 ± 15 ppmv at 1 bar to 500 ± 30 ppmv at 3 bar. We also display the cloud transmittance-NH 3 abundance relationship, and find different behaviour for the NEB, the other belts and the zones. Using a simple cloud model (Lacis and Hansen, 1974;Ackerman and Marley, 2001), we are able to fit this relationship, at least in the NEB, including either NH 3 -ice or NH 4 SH particles with sizes between 10 and 100 µm.

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Section: Introductionmentioning

confidence: 99%

Mapping of Jupiter’s tropospheric NH3 abundance using ground-based IRTF/TEXES observations at 5 µm

Blain

Fouchet

Greathouse

et al. 2018

Icarus

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“…It should be noted that while the extrapolated absorption of the Carlson et al (2016) chromophore extends to 350 nm and our NAIC wavelength range stops at 470 nm, we found that our sensitivity to the location of the shoulder of the chromophore absorption and its slope was sufficient to interpret our results since the slope of the Carlson et al (2016) chromophore is close to linear shortwards of 500 nm. As mentioned previously, Loeffler et al (2016) and Loeffler & Hudson (2018) also presented promising work on a chromophore created by irradiating ammonium hydrosulfide. We did not test this chromophore because of features in this candidate spectrum that are not present in the visible Jovian spectrum, such as the absorption feature at ∼600 nm and a lack of strong absorption at wavelengths longer than 500 nm.…”

Section: Model Atmospherementioning

confidence: 73%

“…Recent laboratory investigations into the chemical identity of the chromophore(s) include a study of irradiated ammonium hydrosulfide (Loeffler et al 2016;Loeffler & Hudson 2018) and an analysis of photolyzed ammonia reacting with acetylene (Carlson et al 2016). Contemporary modeling work using the chromophore discussed in Carlson et al (2016) showed that this ammonia-based molecule, when present in a relatively thin layer directly above the uppermost cloud deck (in addition to a separate stratospheric haze layer), can effectively reproduce spectra of Jupiter's atmosphere as observed by the Visual and Infrared Mapping Spectrometer (VIMS) instrument onboard the Cassini spacecraft during its flyby of Jupiter in late December, 2000 (Baines et al 2014(Baines et al , 2016(Baines et al , 2019Sromovsky et al 2017).…”

Section: Introductionmentioning

confidence: 99%

Vertical Structure and Color of Jovian Latitudinal Cloud Bands during the Juno Era

Dahl¹,

Chanover²,

Orton³

et al. 2020

Preprint

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The identity of the coloring agent(s) in Jupiter's atmosphere and the exact structure of Jupiter's uppermost cloud deck are yet to be conclusively understood. The Crème Brûlée model of Jupiter's tropospheric clouds, originally proposed by Baines et al. (2014) and expanded upon by Sromovsky et al. (2017) and Baines et al. (2019), presumes that the chromophore measured by Carlson et al. ( 2016) is the singular coloring agent in Jupiter's troposphere. In this work, we test the validity of the Crème Brûlée model of Jupiter's uppermost cloud deck using spectra measured during the Juno spacecraft's 5 th perijove pass in March 2017. These data were obtained as part of an international ground-based observing campaign in support of the Juno mission using the NMSU Acousto-optic Imaging Camera (NAIC) at the 3.5-m telescope at Apache Point Observatory in Sunspot, NM. We find that the Crème Brûlée model cloud layering scheme can reproduce Jupiter's visible spectrum both with the Carlson et al. ( 2016) chromophore and with modifications to its imaginary index of refraction spectrum. While the Crème Brûlée model provides reasonable results for regions of Jupiter's cloud bands such as the North Equatorial Belt and Equatorial Zone, we find that it is not a safe assumption for unique weather events, such as the 2016-2017 Southern Equatorial Belt outbreak that was captured by our measurements.

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“…To determine the dose absorbed by each ice, calculations were performed using the software package, Stopping and Range of Ions in Matter (Ziegler et al 2010). The energy of the incident protons was ∼0.9 MeV (Loeffler & Hudson 2018) at a current of 0.5 × 10 −7 A. The total integrated current was converted to fluence (F), in units of p + cm −2 .…”

Section: Experimental Methodsmentioning

confidence: 99%

Radiation-induced D/H Exchange Rate Constants in Aliphatics Embedded in Water Ice

Qasim

Hudson

Materese

2022

ApJ

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Gas-phase and solid-state chemistry in low-temperature interstellar clouds and cores leads to a D/H enhancement in interstellar ices, which is eventually inherited by comets, meteorites, and even planetary satellites. Hence, the D/H ratio has been widely used as a tracer for the origins of extraterrestrial chemistry. However, the D/H ratio can also be influenced by cosmic rays, which are ubiquitous and can penetrate even dense interstellar molecular cores. The effects of such high-energy radiation on deuterium fractionation have not been studied in a quantitative manner. In this study, we present rate constants for radiation-induced D-to-H exchange for fully deuterated small (1–2 C) hydrocarbons embedded in H2O ice at 20 K and H-to-D exchange for the protiated forms of these molecules in D2O ice at 20 K. We observed larger rate constants for H-to-D exchange in the D2O ice versus D-to-H exchange in H2O ice, which we have attributed to the greater bond strength of C–D versus C–H. We find that the H-to-D exchange rate constants are smaller for protiated methane than ethane, in agreement with bond energies from the literature. We are unable to obtain rate constants for the unsaturated and reactive hydrocarbons ethylene and acetylene. Interpretation of the rate constants suggest that D/H exchange products are formed in abundance alongside radiolysis products. We discuss how our quantitative and qualitative data can be used to interpret the D/H ratios of aliphatic compounds observed throughout space.

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Coloring Jupiter's clouds: Radiolysis of ammonium hydrosulfide (NH4SH)

Cited by 14 publications

References 55 publications

Mapping of Jupiter’s tropospheric NH3 abundance using ground-based IRTF/TEXES observations at 5 µm

Mapping of Jupiter’s tropospheric NH3 abundance using ground-based IRTF/TEXES observations at 5 µm

Vertical Structure and Color of Jovian Latitudinal Cloud Bands during the Juno Era

Radiation-induced D/H Exchange Rate Constants in Aliphatics Embedded in Water Ice

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Coloring Jupiter's clouds: Radiolysis of ammonium hydrosulfide (NH4SH)

Cited by 14 publications

References 55 publications

Mapping of Jupiter’s tropospheric NH3 abundance using ground-based IRTF/TEXES observations at 5 µm

Mapping of Jupiter’s tropospheric NH3 abundance using ground-based IRTF/TEXES observations at 5 µm

Vertical Structure and Color of Jovian Latitudinal Cloud Bands during the Juno Era

Radiation-induced D/H Exchange Rate Constants in Aliphatics Embedded in Water Ice

Contact Info

Product

Resources

About

Mapping of Jupiter’s tropospheric NH3 abundance using ground-based IRTF/TEXES observations at 5 µm

Mapping of Jupiter’s tropospheric NH3 abundance using ground-based IRTF/TEXES observations at 5 µm