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REVIEW 2 major objections 4 minor 118 references

Spectroscopic Mapping of Callisto with HST/STIS and Implications for its Surface Composition

T0 review · 2 major / 4 minor · reviewed 2026-08-07 · deepseek-v4-flash

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Pith's one-line read The paper argues that Callisto's 280 nm ratio band, long attributed to sulfur dioxide, is actually an artifact of dividing a leading-hemisphere 320 nm absorption by a trailing-hemisphere 275 nm edge, and that the moon's dark material is…

desk verdict First near-global UV-visible spectral maps of Callisto, with a plausible but not fully closed case that the 280 nm ratio feature is an artifact of the 320 nm and 275 nm bands rather than SO2. read the letter →

arxiv 2506.00151 v1 pith:MX2QIMJX submitted 2025-05-30 astro-ph.EP

M. Ryleigh Davis , Samantha K. Trumbo , Michael E. Brown , Matthew Belyakov This is my paper
classification astro-ph.EP
keywords CallistoGalileansatellitessurfacecompositionUV-visiblespectroscopyHST/STISsulfurdioxidehemisphericratiospectraimpactbasins
verification ladder T0 review T1 audit T2 compute T3 formal

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The reading

Using the first near-global, spatially resolved ultraviolet-visible spectra of Callisto, the paper maps the moon's surface absorptions and reinterprets a key piece of evidence for sulfur chemistry. It argues that the 280 nm band seen only in leading/trailing hemisphere ratio spectra, previously attributed to sulfur dioxide, is not a real surface absorption. Instead, it appears when the leading hemisphere's unrelated 320 nm band is divided by the trailing hemisphere's 275 nm absorption edge. If correct, no sulfur dioxide absorber is required on Callisto's leading hemisphere, and sulfur chemistry is less significant on Callisto than previously proposed. The paper also reports two new absorption features near 230 and 450 nm that may come from irradiated salt, and ties the 820 and 930 nm bands to the giant impact basins.

What carries the argument

The load-bearing object is the hemispheric ratio spectrum, built from spatially resolved HST/STIS measurements, together with maps of individual absorption-band strengths. Dividing a spectrum that contains a 320 nm absorption by one that contains a 275 nm absorption edge creates a local reflectance minimum near 280 nm purely from the shapes of the two unrelated features. The paper demonstrates this with two specific pixels and uses the anti-correlation with the 275 nm edge and the correlation with the 320 nm band to argue that no sulfur dioxide or ozone absorber is needed.

What would settle it

Compute leading/trailing ratio spectra using only surface pixels that show neither a 320 nm band nor a 275 nm edge; if a 280 nm feature still appears, the two-band explanation fails, while if it disappears, the sulfur dioxide requirement is removed. A second check would compare the measured 280 nm band's width and center with the product of the two mapped bands rather than with sulfur dioxide laboratory spectra.

Watch

Extended reading notes

Core claim

The central discovery is that Callisto's 280 nm ratio feature, long used as evidence for sulfur dioxide, is a division artifact. By constructing pixel-by-pixel maps of band strengths, the authors show that the ratio feature strongly anti-correlates with the trailing-hemisphere 275 nm absorption edge and strongly correlates with the leading-hemisphere 320 nm absorption. Ratioing just two individual spectra, one containing the 320 nm band and one containing the 275 nm edge, reproduces the broad 280 nm feature without invoking any additional absorber. The paper concludes that SO2 and O3 are not required to explain the ratio band, and finds little ultraviolet-visible evidence for sulfur-bearing species anywhere on Callisto.

Load-bearing premise

The reinterpretation assumes the 320 nm and 275 nm features are real intrinsic surface absorptions with the shapes inferred from the continuum fits; if either feature is an artifact of the data correction or continuum choices, the 280 nm ratio band could still require an additional absorber such as sulfur dioxide.

Editorial extensions

If this is right

  • If the reinterpretation holds, previous estimates of sulfur dioxide abundance on Callisto's leading hemisphere lose their primary ultraviolet evidence, and sulfur-driven surface models must be revised downward.
  • Callisto's ultraviolet-visible spectrum points toward a carbon- and organic-dominated dark material, with sulfur playing at most a minor role, consistent with recent near-infrared results.
  • The 320 nm band's confinement to the Asgard and Valhalla impact regions and the 275 nm edge's confinement to the trailing hemisphere imply regional surface compositions rather than a global exogenic sulfur layer.
  • The two newly reported bands near 230 and 450 nm, if confirmed as irradiated sodium chloride, would add Callisto to the growing list of Galilean satellites with possible surface salts.
  • The association of the 820 and 930 nm absorptions with the large impact basins suggests iron-bearing silicates formed by impact melt or excavated from the subsurface, not delivered dust.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

  • The ratio-artifact logic suggests that other hemispheric ratio features on icy satellites should be checked against pixel-level maps of the underlying bands before assigning new absorbers, a test that could be applied to Ganymede's broadened 260 nm feature as well.
  • If the 275 nm edge really comes from irradiation-carbonized organics, then far-ultraviolet reflectance below 200 nm should darken with increasing irradiation dose; future ultraviolet spectroscopy could test this prediction directly.
  • The proposed sodium chloride identification could be strengthened by checking whether the 230 and 450 nm band strengths are spatially correlated with each other and with fresh crater ejecta, something the paper could not map confidently.
  • The fate of magnetospheric sulfur on Callisto may lie outside STIS's wavelength range: if the sulfur is converted to hydrated sulfuric acid, its main electronic absorption sits below 200 nm, so far-ultraviolet observations would be the decisive check.
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Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Referee Report

2 major / 4 minor

Summary. The paper presents new HST/STIS spatially resolved spectra of Callisto from 200 to 1000 nm, maps several spectral features (near-UV downturn, 700–1000 nm slope, 820/930 nm absorptions, 320 nm band, 275 nm absorption edge, and the 280 nm leading/trailing ratio feature), reports two new absorption bands near 230 and 450 nm tentatively attributed to irradiated NaCl, and proposes that the previously reported 280 nm SO2 band in leading/trailing ratio spectra is an artifact of dividing a leading-hemisphere 320 nm band by a trailing-hemisphere 275 nm absorption edge. The authors conclude that an additional absorber such as SO2 is not required to explain the ratio feature, and they discuss implications for sulfur chemistry and the organic/carbon composition of Callisto's dark material.

Significance. If the reinterpretation of the 280 nm feature holds, it removes a key piece of evidence for sulfur-bearing species on Callisto's leading hemisphere and supports a surface chemistry dominated by carbon/organic materials, with implications for the Galilean satellite system as a whole. The data set is the first near-global, spatially resolved UV-visible spectroscopic survey of Callisto, and the maps of the 320 nm and 275 nm features are new and valuable. The manuscript is appropriately hedged in several places: it explicitly does not rule out small SO2/O3 contributions (Section 5.5), and it clearly states the difficulties in mapping the 230 and 450 nm features (Section 4.5). The data are publicly available (doi: 10.17909/q7h0-3j07), which is a strength for reproducibility.

major comments (2)
  1. [Section 5.5, Fig. 10b] The central claim that the 280 nm ratio feature is fully explained by dividing the 320 nm leading-hemisphere band by the 275 nm trailing-hemisphere edge is supported only by a two-pixel example and by the correlations in Fig. 8b,c. The paper does not provide a quantitative reconstruction of the observed disk-integrated or average leading/trailing ratio spectrum from the independently mapped 320 nm and 275 nm features. Because Section 4.4 states that the 320 nm band is constrained to the Asgard and Valhalla regions while Section 4.7 and Fig. 8a show the 280 nm ratio feature across the leading hemisphere, the mechanism needs to be tested for pixels without a detected 320 nm band. I request a forward model that uses the measured band shapes and strengths to predict the ratio spectrum (e.g., over 230–405 nm) for representative pixels and compares the residual to the noise, to determine whether any significant 280 nm absorption remains outside the 320 nm-bearing regions.
  2. [Section 4.6] The 275 nm band-area map is constructed by dividing each spectrum by a base spectrum formed from five pixels selected for having the smallest 230–270 nm slopes; this data-dependent choice is a free parameter that could imprint a spectral shape onto the map. Although the independent 230–270 nm slope map (Fig. 7a) correlates strongly (R = 0.914) with the band-area map, the band-area map is the one used in the scatter plots of Fig. 8 and in the two-pixel demonstration of Fig. 10b. The authors should test the sensitivity of the 280 nm reconstruction to the choice of base pixels (e.g., using different pixel sets, an average trailing-hemisphere spectrum, or the slope map directly) to confirm that the result does not depend on this selection.
minor comments (4)
  1. [Section 5.5, Fig. 10b] The text says 'their ratio (orange/blue)' for the blue leading-hemisphere pixel (25°W, 10°N) and orange trailing-hemisphere pixel (230°W, 15°S), which would be trailing/leading, not leading/trailing as described in the abstract and Section 5.5; please clarify the ratio direction in the text and figure caption.
  2. [Section 2 (Introduction)] Typo in the first paragraph: 'to the the leading/sub-Jovian hemisphere' should read 'to the leading/sub-Jovian hemisphere.'
  3. [Figure 10b caption] The caption contains 'diving a spectrum' where 'dividing' is intended.
  4. [Section 6] Typo: 'with the largest affects' should read 'with the largest effects.'

Circularity Check

0 steps flagged · score 0.0 of 10

No significant circularity: the reinterpretation of the 280 nm ratio feature is an arithmetic demonstration using independently mapped 320 nm and 275 nm features, not a fitted or self-referential prediction.

full rationale

The paper's central claim—that the 280 nm leading/trailing ratio band is an artifact of dividing the leading-hemisphere 320 nm absorption by the trailing-hemisphere 275 nm edge—is not circular. The 320 nm band and 275 nm edge are mapped directly from individual pixel spectra using continuum fits and slope/band-area measurements (Sections 4.4 and 4.6), independent of the leading/trailing ratio construction that produces the 280 nm feature. The demonstration in Section 5.5 selects two pixels with strong 320 nm and 275 nm features and shows that their ratio reproduces the apparent 280 nm band; this is an existence proof of the arithmetic mechanism, not a fitted parameter renamed as a prediction. The spatial correlations in Figure 8b,c are between independently measured band-area maps, not between the same quantity defined twice. No uniqueness theorem, fitted input, or ansatz is imported from the authors' prior work to force the conclusion. Self-citations occur for irradiated NaCl laboratory spectra and Europa detections, but these are external benchmark data and the NaCl attribution is explicitly tentative ('might be attributed', 'plausibly'), with alternative explanations acknowledged. The derivation chain is self-contained against the HST/STIS observations and external spectral libraries, so no circularity is found.

Assumptions & free parameters 2 free parameters · 4 assumptions · 0 invented entities

No new particles, forces, or physical entities are proposed. Candidate surface components such as irradiated NaCl, organics, phyllosilicates, and carbonized material are known materials applied as tentative spectral matches, with no external falsifiable handle beyond the observed bands themselves.

free parameters (2)
  • Spectral continuum and band-integration wavelength bounds = e.g., 360-410 nm for UV slope, 680-1000 nm for NIR slope, 262-370 nm for 320 nm band, 660-995 nm for 820/930 nm bands…
    Chosen by hand to avoid overlapping features, with manual per-pixel adjustments for band areas. The authors state small slope-bound changes give consistent results, but the 230 and 450 nm features could not be mapped robustly across continuum choices.
  • 275 nm base-spectrum pixel selection = Five pixels near (141W,42N), (154W,39N), (150W,45N), (145W,51N), (144W,49N)
    Used as an assumed edge-free reference to define 220-275 nm band areas. No sensitivity test to this selection is reported.
assumptions (4)
  • domain assumption HST/STIS pipeline calibration, solar spectrum division, and slit-loss and defringing correction produce reflectance spectra whose spatial and spectral features are intrinsic to Callisto.
    Invoked throughout Section 2. The correction multiplies each spectrum by a spline fit to ground-based disk-integrated data, so artifacts in that reference propagate into all maps.
  • domain assumption Normalized spectra with pixels beyond 60 degrees from disk center removed are free of significant photometric phase-angle effects.
    Section 2 states no photometric correction is applied because spectra are normalized. This assumes residual phase effects do not create the mapped bands.
  • domain assumption The 320 nm band and 275 nm edge are real absorptions separable from the broad UV continuum by linear fits.
    Sections 4.4 and 4.6 define these features through continuum fits that exclude the band regions. The 280 nm reinterpretation depends on this separability.
  • domain assumption Room-temperature and irradiated laboratory spectra are representative enough to support tentative band assignments on Callisto's cryogenic surface.
    Section 5 repeatedly notes that most lab spectra are room temperature and that future cryogenic work is needed. Identifications are presented as preliminary.

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Cite this review

Pith. "Pith review of Spectroscopic Mapping of Callisto with HST/STIS and Implications for its Surface Composition." pith.science (2026). https://pith.science/paper/MX2QIMJX

@misc{pith2026250600151,
  author       = {Pith},
  title        = {Pith review of: Spectroscopic Mapping of Callisto with HST/STIS and Implications for its Surface Composition},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/MX2QIMJX}},
  note         = {Machine review of arXiv:2506.00151}
}
read the original abstract

We present global, spatially resolved ultraviolet-visible spectra of Callisto obtained with HST/STIS and explore possible compositions of Callisto's surface material. We map the strength of a widespread downturn toward the near-UV and the NIR spectral slope from 700 to 1000 nm, which varies from slightly blue (reflectance decreasing from 700 to 1000 nm) to red (reflectance increasing) across Callisto's surface. Globally, bright water-ice-rich regions tend to have neutral or blue NIR slopes and a shallower near-UV downturn, while darker material is associated with red NIR slopes and stronger near-UV absorption. Broad absorptions near 820 and 930 nm are spatially correlated with the Asgard and Valhalla impact basins and may be associated with iron-bearing silicates. An absorption edge near 275 nm maps primarily to Callisto's trailing hemisphere, and a 320 nm absorption most prevalent within and surrounding Asgard and Valhalla may be related to organics. We report two new absorption features near 230 and 450 nm which might be attributed to irradiated NaCl. We find little evidence for sulfur-bearing species at UV-visible wavelengths and suggest that a 280 nm band seen only in leading/trailing hemisphere ratio spectra and previously attributed to SO2 is better explained as a consequence of dividing the unrelated 320 nm leading hemisphere band by the trailing hemisphere 275 nm absorption edge. Spatial variations in spectral features suggest that Callisto's dark material composition varies regionally, reflecting a mix of endogenic and exogenic sources and radiolytic alteration.

Figures

Figures reproduced from arXiv: 2506.00151 by the authors.

Figure 1
Figure 1. Example HST spectra from 200 to 1000 nm of a few representative regions on Callisto. The location of each spectrum is indicated by a numbered circle on the map (a) with a corresponding color to the plotted spectrum (b). Each spectrum is calculated by averaging the UV and visible pixels which intersect a circle with a radius of 2◦ about the point of interest, and combining the resulting UV and visible spectra. Spectr… view at source ↗
Figure 2
Figure 2. Maps showing Callisto’s bolometric albedo (a; from Camarca et al. 2023) compared with the spectral slope from 360 to 410 nm (b), which measures the strength of the near-UV downturn (redder slope = stronger downturn). The per-pixel estimated 1σ error on the 360 to 410 nm slope ranged from ±4.9×10−5 to ±2.2×10−4 , and the minimum (black) and maximum (grey) estimated error is shown on the colorbar. On both maps, the la… view at source ↗
Figure 3
Figure 3. (a) Map showing the NIR spectral slope from 700 to 1000 nm. The per-pixel estimated 1σ error on the slope ranged from ±3.3×10−6 to ±1.5×10−5 , and the minimum (black) and maximum (grey) estimated error is shown on the colorbar. Most of the surface has a neutral or red NIR slope except for the regions at southern latitudes and near Heimdall and Lofn that show an abundance of icy material and the central zones of the … view at source ↗
Figures from the paper (8 more)
Figure 4
Figure 4. Figure 4: A selection of spectra showing regions on Cal￾listo’s surface where there is a clear 820 nm absorption with little to no 930 nm absorption (1: (76◦ W, 20◦ N)), a clear 930 nm absorption with a relatively weaker 820 nm absorp￾tion (2: (312◦ W, 12◦ S)), and relatively st…
Figure 5
Figure 5. Figure 5: Map showing the calculated band area of the combined 820 and 930 nm absorption features (a), along with scatter plots (b) demonstrating that there is no notable correlation between the relative albedo of the dark material and the strength of the 820 and 930 nm bands an…
Figure 6
Figure 6. Figure 6: (a) The map of the strength of the 320 nm absorption demonstrates that it is largely constrained to the regions within and surrounding the Asgard and Valhalla impact basins which leads to clear hemispheric asymmetry. The scatter plots (b) reveal a moderately strong neg…
Figure 7
Figure 7. Figure 7: Maps showing our two proxies for the strength of the 275 nm absorption edge- (a) the normalized slope from 230 to 270 nm , and (b) the integrated band area (from 220 nm to 275 nm) after dividing by a base spectrum constructed from five pixels identified as having the w…
Figure 8
Figure 8. Figure 8: (a) Map showing the calculated band area of the 280 nm ratio feature for spectra ratioed with the center of the trailing hemisphere. Negative values represent pixels where the ratio spectrum is above the linear continuum and there is no apparent 280 nm feature present.…
Figure 9
Figure 9. Figure 9: Comparison between select Callisto spectra and some laboratory spectra discussed in the text. The color and associated number for each Callisto spectrum correspond with the locations mapped in Figure 1a and the longitude and latitude are listed in panel a. Examples of …
Figure 10
Figure 10. Figure 10: (a) Callisto’s 280 nm absorption shows up in leading hemisphere spectra when ratioed against the trailing hemi￾sphere. Europa’s trailing/leading hemisphere ratio spectrum (blue) shows a clear 280 nm band which matches the laboratory spectrum of irradiated SO2 ice that…
Figure 11
Figure 11. Figure 11: Comparison of HST/STIS UV (left) and visible (right) spectra of the leading and trailing hemispheres of Callisto, Ganymede, and Europa, and a patch of bright white (sulfur rich) material on Io’s leading hemisphere. The leading and trailing averages for Europa, Ganymed…

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Works this paper leans on

118 extracted references · 62 canonical work pages

  1. [1]

    2018, Astronomy & Astrophysics, 620, A123, doi: 10.1051/0004-6361/201834057

    Accolla, M., Pellegrino, G., Baratta, G., et al. 2018, Astronomy & Astrophysics, 620, A123, doi: 10.1051/0004-6361/201834057

    work page doi:10.1051/0004-6361/201834057 2018

  2. [2]

    L., Cahill, J

    Bandfield, J. L., Cahill, J. T., Carter, L. M., et al. 2017, Icarus, 283, 282, doi: 10.1016/j.icarus.2016.05.013

    work page doi:10.1016/j.icarus.2016.05.013 2017

  3. [3]

    M., Trumbo, S

    Becker, T. M., Trumbo, S. K., Molyneux, P. M., et al. 2022, The Planetary Science Journal, 3, 129, doi: 10.3847/PSJ/ac69eb Bell III, J., & Ansty, T. 2007, Icarus, 191, 581, doi: 10.1016/j.icarus.2007.05.019

    work page doi:10.3847/psj/ac69eb 2022

  4. [4]

    R., & Robinson, D

    Bevington, P. R., & Robinson, D. K. 2003, Data Reduction and Error Analysis for the Physical Sciences (McGraw-Hill)

    2003

  5. [5]

    2017, Astronomy & Astrophysics, 608, A67, doi: 10.1051/0004-6361/201630361

    Bhatt, M., Reddy, V., Schindler, K., et al. 2017, Astronomy & Astrophysics, 608, A67, doi: 10.1051/0004-6361/201630361

    work page doi:10.1051/0004-6361/201630361 2017

  6. [6]

    L., Bell, J., & Moersch, J

    Bishop, J. L., Bell, J., & Moersch, J. E., eds. 2019, Remote Compositional Analysis: Techniques for Understanding

    2019

  7. [7]

    2024, Astronomy & Astrophysics, 681, A27, doi: 10.1051/0004-6361/202347326

    Bockelee-Morvan, D., Lellouch, E., Poch, O., et al. 2024, Astronomy & Astrophysics, 681, A27, doi: 10.1051/0004-6361/202347326

    work page doi:10.1051/0004-6361/202347326 2024

  8. [8]

    2016, Icarus, 277, 424, doi: 10.1016/j.icarus.2016.05.026

    Boduch, P., Brunetto, R., Ding, J., et al. 2016, Icarus, 277, 424, doi: 10.1016/j.icarus.2016.05.026

    work page doi:10.1016/j.icarus.2016.05.026 2016

Show all 118 references
  1. [9]

    F., Vokrouhlick` y, D., Nesvorn` y, D., & Moore, J

    Bottke, W. F., Vokrouhlick` y, D., Nesvorn` y, D., & Moore, J. M. 2013, Icarus, 223, 775, doi: 10.1016/j.icarus.2013.01.008

    2013 doi

  2. [10]

    F., Vokrouhlick` y, D., Nesvorn` y, D., et al

    Bottke, W. F., Vokrouhlick` y, D., Nesvorn` y, D., et al. 2024, The Planetary Science Journal, 5, 88, doi: 10.3847/PSJ/ad29f4

    2024 doi

  3. [11]

    E., Denman, W

    Brown, M. E., Denman, W. T., & Trumbo, S. K. 2022, The Planetary Science Journal, 3, 28, doi: 10.3847/PSJ/ac457f

    2022 doi

  4. [12]

    Buratti, B. J. 1991, Icarus, 92, 312, doi: 10.1016/0019-1035(91)90054-W

    1991 doi

  5. [13]

    Burns, R. G. 1993, Mineralogical applications of crystal field theory No. 5 (Cambridge university press)

    1993

  6. [14]

    M., & Clark, R

    Calvin, W. M., & Clark, R. N. 1991, Icarus, 89, 305, doi: 10.1016/0019-1035(91)90180-2 —. 1993, Icarus, 104, 69, doi: 10.1006/icar.1993.1083

    1991

  7. [15]

    M., Clark, R

    Calvin, W. M., Clark, R. N., Brown, R. H., & Spencer, J. R. 1995, Journal of Geophysical Research: Planets, 100, 19041, doi: 10.1029/94JE03349

    1995 doi

  8. [16]

    2023, The Planetary Science Journal, 4, 142, doi: 10.3847/PSJ/aceb68

    Camarca, M., de Kleer, K., Butler, B., et al. 2023, The Planetary Science Journal, 4, 142, doi: 10.3847/PSJ/aceb68

    2023 doi

  9. [17]

    2002, Icarus, 157, 456, doi: 10.1006/icar.2002.6858

    Yavrouian, A. 2002, Icarus, 157, 456, doi: 10.1006/icar.2002.6858

    2002

  10. [18]

    2009, Europa, 283

    Carlson, R., Calvin, W., Dalton, J., et al. 2009, Europa, 283

    2009

  11. [19]

    1999a, Science, 286, 97, doi: 10.1126/science.286.5437.97

    Carlson, R., Johnson, R., & Anderson, M. 1999a, Science, 286, 97, doi: 10.1126/science.286.5437.97

    doi

  12. [20]

    W., Anderson, M

    Carlson, R. W., Anderson, M. S., Johnson, R. E., et al. 1999b, Science, 283, 2062, doi: 10.1126/science.283.5410.2062

  13. [21]

    J., Nordheim, T

    Cartwright, R. J., Nordheim, T. A., Cruikshank, D. P., et al. 2020, The Astrophysical Journal, 902, L38, doi: 10.3847/2041-8213/abbdae

    2020 doi

  14. [22]

    J., Villanueva, G

    Cartwright, R. J., Villanueva, G. L., Holler, B. J., et al. 2024, The Planetary Science Journal, 5, 60, doi: 10.3847/PSJ/ad23e6

    2024 doi

  15. [23]

    2024, Monthly Notices of the Royal Astronomical Society, 527, 11327, doi: 10.1093/mnras/stad3829

    Chen, Z., Yang, K., & Liu, X. 2024, Monthly Notices of the Royal Astronomical Society, 527, 11327, doi: 10.1093/mnras/stad3829

    2024 doi

  16. [24]

    Clark, R. N. 1980, Icarus, 44, 388, doi: 10.1016/0019-1035(80)90033-0

    1980 doi

  17. [25]

    N., & Mc Cord, T

    Clark, R. N., & Mc Cord, T. B. 1980, Icarus, 41, 323, doi: 10.1016/0019-1035(80)90217-1

    1980 doi

  18. [26]

    N., Cruikshank, D

    Clark, R. N., Cruikshank, D. P., Jaumann, R., et al. 2012, Icarus, 218, 831, doi: 10.1016/j.icarus.2012.01.008 34

    2012 doi

  19. [27]

    2015, Mineral and rock sample database

    Cloutis, E. 2015, Mineral and rock sample database. Planetary Spectrophotometer Facility (PSF), University of Winnipeg

    2015

  20. [28]

    2011a, Icarus, 212, 180, doi: 10.1016/j.icarus.2010.12.009

    Mann, P. 2011a, Icarus, 212, 180, doi: 10.1016/j.icarus.2010.12.009

    2010 doi

  21. [29]

    2011b, Icarus, 216, 309, doi: 10.1016/j.icarus.2011.09.009

    Cloutis, E., Hudon, P., Hiroi, T., Gaffey, M., & Mann, P. 2011b, Icarus, 216, 309, doi: 10.1016/j.icarus.2011.09.009

    2011 doi

  22. [30]

    2013, Icarus, 223, 850, doi: 10.1016/j.icarus.2013.02.003

    Cloutis, E., Izawa, M., Pompilio, L., et al. 2013, Icarus, 223, 850, doi: 10.1016/j.icarus.2013.02.003

    2013 doi

  23. [31]

    Cloutis, E. A. 2002, Journal of Geophysical Research: Planets, 107, 6, doi: 10.1029/2001JE001590

    2002 doi

  24. [32]

    A., Hawthorne, F

    Cloutis, E. A., Hawthorne, F. C., Mertzman, S. A., et al. 2006, Icarus, 184, 121, doi: 10.1016/j.icarus.2006.04.003

    2006 doi

  25. [33]

    F., Johnson, R

    Cooper, J. F., Johnson, R. E., Mauk, B. H., Garrett, H. B., & Gehrels, N. 2001, Icarus, 149, 133, doi: 10.1006/icar.2000.6498

    2001

  26. [34]

    P., Owen, T

    Cruikshank, D. P., Owen, T. C., Dalle Ore, C., et al. 2005, Icarus, 175, 268, doi: 10.1016/j.icarus.2004.09.003 de Marcellus, P., Fresneau, A., Brunetto, R., et al. 2017, Monthly Notices of the Royal Astronomical Society, 464, 114, doi: 10.1093/mnras/stw2292 De Sanctis, M. C.,...

    2005 doi

  27. [35]

    1998, in Lunar and Planetary Science Conference No

    Denk, T., Neukum, G., McCord, T., et al. 1998, in Lunar and Planetary Science Conference No. 1676, 1676

    1998

  28. [36]

    1999, in Lunar and Planetary Science Conference, 1877

    Denk, T., Neukum, G., Wagner, R., et al. 1999, in Lunar and Planetary Science Conference, 1877

    1999

  29. [37]

    1984, Astrophysical Journal, Part 1 (ISSN 0004-637X), vol

    Duley, W. 1984, Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 287, Dec. 15, 1984, p. 694-696. Research supported by the Natural Sciences and Engineering Research Council of Canada., 287, 694

    1984

  30. [38]

    2018, The Astrophysical Journal, 853, 71, doi: 10.3847/1538-4357/aaa24d

    Escobar-Cerezo, J., Penttil¨ a, A., Kohout, T., et al. 2018, The Astrophysical Journal, 853, 71, doi: 10.3847/1538-4357/aaa24d

    2018 doi

  31. [39]

    2021, Icarus, 364, 114462, doi: 10.1016/j.icarus.2021.114462

    Faure, M., Quirico, E., Faure, A., et al. 2021, Icarus, 364, 114462, doi: 10.1016/j.icarus.2021.114462

    2021

  32. [40]

    J., & McCord, T

    Gaffey, M. J., & McCord, T. B. 1978, Space Science Reviews, 21, 555, doi: 10.1007/BF00240908

    1978 doi

  33. [41]

    2017, The Astrophysical journal letters, 848, L5, doi: 10.3847/2041-8213/aa8cc4

    Gavilan, L., Broch, L., Carrasco, N., Fleury, B., & Vettier, L. 2017, The Astrophysical journal letters, 848, L5, doi: 10.3847/2041-8213/aa8cc4

    2017 doi

  34. [42]

    1973, Chemical Physics Letters, 21, 318, doi: 10.1016/0009-2614(73)80145-9

    Gosavi, R., DeSorgo, M., Gunning, H., & Strausz, O. 1973, Chemical Physics Letters, 21, 318, doi: 10.1016/0009-2614(73)80145-9

    1973 doi

  35. [43]

    1980, Icarus, 44, 373, doi: 10.1016/0019-1035(80)90032-9

    Gradie, J., Thomas, P., & Veverka, J. 1980, Icarus, 44, 373, doi: 10.1016/0019-1035(80)90032-9

    1980 doi

  36. [44]

    M., Mainzer, A

    Grav, T., Bauer, J. M., Mainzer, A. K., et al. 2015, The Astrophysical Journal, 809, 3, doi: 10.1088/0004-637X/809/1/3

    2015 doi

  37. [45]

    E., & Wagner, R

    Greeley, R., Klemaszewski, J. E., & Wagner, R. 2000, Planetary and Space Science, 48, 829, doi: 10.1016/S0032-0633(00)00050-7

    2000 doi

  38. [46]

    2023, LPI Contributions, 2806, 1432

    Gritsevich, M., & Kreslavsky, M. 2023, LPI Contributions, 2806, 1432

    2023

  39. [47]

    P., & Brown, M

    Hand, K. P., & Brown, M. E. 2013, The Astrophysical Journal Letters, 766, L21, doi: 10.1088/2041-8205/766/2/L21

    2013 doi

  40. [48]

    R., Barth, C

    Hendrix, A. R., Barth, C. A., Stewart, A. I. F., Hord, C. W., & Lane, A. L. 1999, in Proc. 30th Lunar and Planetary Sci. Conf. (Houston: LPI)

    1999

  41. [49]

    R., Cassidy, T

    Hendrix, A. R., Cassidy, T. A., Johnson, R. E., Paranicas, C., & Carlson, R. W. 2011, Icarus, 212, 736, doi: 10.1016/j.icarus.2011.01.023

    2011 doi

  42. [50]

    R., Domingue, D

    Hendrix, A. R., Domingue, D. L., & King, K. 2005, Icarus, 173, 29, doi: 10.1016/j.icarus.2004.06.017

    2005 doi

  43. [51]

    R., Filacchione, G., Paranicas, C., Schenk, P., & Scipioni, F

    Hendrix, A. R., Filacchione, G., Paranicas, C., Schenk, P., & Scipioni, F. 2018, Icarus, 300, 103, doi: 10.1016/j.icarus.2017.08.037

    2018 doi

  44. [52]

    R., Hansen, C

    Hendrix, A. R., Hansen, C. J., & Holsclaw, G. M. 2010, Icarus, 206, 608, doi: 10.1016/j.icarus.2009.11.007

    2010 doi

  45. [53]

    R., & Johnson, R

    Hendrix, A. R., & Johnson, R. E. 2008, The Astrophysical Journal, 687, 706, doi: 10.1086/591491

    2008 doi

  46. [54]

    2003, in Lunar and Planetary Science Conference, 1925

    Hibbitts, C., Hansen, G., McCord, T., & Stephan, K. 2003, in Lunar and Planetary Science Conference, 1925

    2003

  47. [55]

    2002, Journal of Geophysical Research: Planets, 107, 14, doi: 10.1029/2000JE001412

    Greeley, R. 2002, Journal of Geophysical Research: Planets, 107, 14, doi: 10.1029/2000JE001412

    2002 doi

  48. [56]

    A., McCord, T

    Hibbitts, C. A., McCord, T. B., & Hansen, G. B. 2000, Journal of Geophysical Research: Planets, 105, 22541, doi: 10.1029/1999JE001101

    2000 doi

  49. [57]

    D., & Moore, J

    Howard, A. D., & Moore, J. M. 2008, Geophysical Research Letters, 35, doi: 10.1029/2007GL032618

    2008 doi

  50. [58]

    R., & Ashley, R

    Hunt, G. R., & Ashley, R. P. 1979, Economic Geology, 74, 1613, doi: 10.2113/gsecongeo.74.7.1613

    1979 doi

  51. [59]

    2009, Europa, 21, 507

    Johnson, R., Burger, M., Cassidy, T., et al. 2009, Europa, 21, 507

    2009

  52. [60]

    2004, Jupiter: the planet, satellites and magnetosphere, ed

    Johnson, R., Carlson, R., Cooper, J., et al. 2004, Jupiter: the planet, satellites and magnetosphere, ed. F. Bagenal, T. E. Dowling, W. B. McKinnon, & W. McKinnon, Vol. 1 (Cambridge University Press), 485–512

    2004

  53. [61]

    Johnson, R. E. 2004, The Astrophysical Journal, 609, L99, doi: 10.1086/422912

    2004 doi

  54. [62]

    V., & McCord, T

    Johnson, T. V., & McCord, T. B. 1970, Icarus, 13, 37, doi: 10.1016/0019-1035(70)90115-6

    1970 doi

  55. [63]

    M., Kaiser, R

    Jones, B. M., Kaiser, R. I., & Strazzulla, G. 2014, The Astrophysical Journal, 781, 85, doi: 10.1088/0004-637X/781/2/85

    2014 doi

  56. [64]

    2007, Spectroscopy of organic compounds (New age international) 35

    Kalsi, P. 2007, Spectroscopy of organic compounds (New age international) 35

    2007

  57. [65]

    L., Pieters, C

    Klima, R. L., Pieters, C. M., & Dyar, M. D. 2007, Meteoritics & Planetary Science, 42, 235, doi: 10.1111/j.1945-5100.2007.tb00230.x

    2007

  58. [66]

    2014, Icarus, 237, 75, doi: 10.1016/j.icarus.2014.04.004

    Kohout, T., ˇCuda, J., Filip, J., et al. 2014, Icarus, 237, 75, doi: 10.1016/j.icarus.2014.04.004

    2014 doi

  59. [67]

    F., Clark, R

    Kokaly, R. F., Clark, R. N., Swayze, G. A., et al. 2017, USGS Spectral Library Version 7, Report 1035, Reston, V A, doi: 10.3133/ds1035

    2017 doi

  60. [68]

    2021, Icarus, 364, 114479, doi: 10.1016/j.icarus.2021.114479

    Laczniak, D., Thompson, M., Christoffersen, R., et al. 2021, Icarus, 364, 114479, doi: 10.1016/j.icarus.2021.114479

    2021

  61. [69]

    L., & Domingue, D

    Lane, A. L., & Domingue, D. L. 1997, Geophysical research letters, 24, 1143, doi: 10.1029/97GL00884

    1997 doi

  62. [70]

    L., Nelson, R

    Lane, A. L., Nelson, R. M., & Matson, D. L. 1981, Nature, 292, 38, doi: 10.1038/292038a0

    1981 doi

  63. [71]

    N., & Jacobson, S

    Liu, B., Raymond, S. N., & Jacobson, S. A. 2022, Nature, 604, 643, doi: 10.1038/s41586-022-04535-1

    2022 doi

  64. [72]

    2019, Planetary and Space Science, 166, 23, doi: 10.1016/j.pss.2018.07.014

    Liuzzo, L., Simon, S., & Regoli, L. 2019, Planetary and Space Science, 166, 23, doi: 10.1016/j.pss.2018.07.014

    2019 doi

  65. [73]

    J., & Hudson, R

    Loeffler, M. J., & Hudson, R. L. 2016, The Astrophysical Journal Letters, 833, L9, doi: 10.3847/2041-8213/833/1/L9

    2016 doi

  66. [74]

    1991, Astronomical Journal (ISSN 0004-6256), vol

    Luu, J. 1991, Astronomical Journal (ISSN 0004-6256), vol. 102, Sept. 1991, p. 1213-1225., 102, 1213

    1991

  67. [75]

    J., Hand, K

    Mahjoub, A., Poston, M. J., Hand, K. P., et al. 2016, The Astrophysical Journal, 820, 141, doi: 10.3847/0004-637X/820/2/141 Mc Fadden, L. A., Bell, J. F., & Mc Cord, T. B. 1980, Icarus, 44, 410, doi: 10.1016/0019-1035(80)90034-2

    2016 doi

  68. [76]

    B., Carlson, R

    McCord, T. B., Carlson, R. W., Smythe, W. D., et al. 1997, Science, 278, 271, doi: 10.1126/science.278.5336.271

    1997 doi

  69. [77]

    B., Hansen, G

    McCord, T. B., Hansen, G. B., Clark, R. N., et al. 1998, Journal of Geophysical Research: Planets, 103, 8603, doi: 10.1029/98JE00788

    1998 doi

  70. [78]

    D., Whited, L

    McDonald, G. D., Whited, L. J., DeRuiter, C., et al. 1996, Icarus, 122, 107, doi: 10.1006/icar.1996.0112

    1996

  71. [79]

    M., Asphaug, E., Morrison, D., et al

    Moore, J. M., Asphaug, E., Morrison, D., et al. 1999, Icarus, 140, 294, doi: 10.1006/icar.1999.6132

    1999

  72. [80]

    M., Chapman, C

    Moore, J. M., Chapman, C. R., Bierhaus, E. B., et al. 2004, Jupiter: the planet, satellites and magnetosphere, ed. F. Bagenal, T. E. Dowling, W. B. McKinnon, & W. McKinnon, Vol. 1 (Cambridge University Press), 397–426

    2004

  73. [81]

    V., Golden, D., & Bell III, J

    Morris, R. V., Golden, D., & Bell III, J. F. 1997, Journal of Geophysical Research: Planets, 102, 9125, doi: 10.1029/96JE03993

    1997 doi

  74. [82]

    V., Lauer Jr, H

    Morris, R. V., Lauer Jr, H. V., Lawson, C. A., et al. 1985, Journal of Geophysical Research: Solid Earth, 90, 3126, doi: 10.1029/JB090iB04p03126

    1985 doi

  75. [83]

    D., & Lazarewicz, A

    Morrison, D., Morrison, N. D., & Lazarewicz, A. R. 1974, Icarus, 23, 399, doi: 10.1016/0019-1035(74)90058-X

    1974 doi

  76. [84]

    I., & Nash, D

    Moses, J. I., & Nash, D. B. 1991, Icarus, 89, 277, doi: 10.1016/0019-1035(91)90179-W

    1991 doi

  77. [85]

    1980, Geophysical Research Letters, 7, 665, doi: 10.1029/GL007i009p00665

    Nash, D., Fanale, F., & Nelson, R. 1980, Geophysical Research Letters, 7, 665, doi: 10.1029/GL007i009p00665

    1980 doi

  78. [86]

    M., Lane, A

    Nelson, R. M., Lane, A. L., Matson, D. L., et al. 1987, Icarus, 72, 358, doi: 10.1016/0019-1035(87)90180-1 Nesvorn` y, D., Vokrouhlick` y, D., Bottke, W. F., & Levison, H. F. 2018, Nature Astronomy, 2, 878, doi: 10.1038/s41550-018-0564-3

    1987 doi

  79. [87]

    S., Johnson, R

    Noll, K. S., Johnson, R. E., Lane, A. L., Domingue, D. L., & Weaver, H. A. 1996, Science, 273, 341, doi: 10.1126/science.273.5273.341

    1996 doi

  80. [88]

    S., Johnson, R

    Noll, K. S., Johnson, R. E., McGrath, M. A., & Caldwell, J. J. 1997, Geophysical Research Letters, 24, 1139, doi: 10.1029/97GL00876

    1997 doi

  81. [89]

    2004, Advances in Space Research, 33, 49, doi: 10.1016/j.asr.2003.03.002

    Palumbo, M., Ferini, G., & Baratta, G. 2004, Advances in Space Research, 33, 49, doi: 10.1016/j.asr.2003.03.002

    2004 doi

  82. [90]

    M., & Hiroi, T

    Pieters, C. M., & Hiroi, T. 2004, in Lunar and Planetary Science Conference, 1720

    2004

  83. [91]

    J., Mahjoub, A., Ehlmann, B

    Poston, M. J., Mahjoub, A., Ehlmann, B. L., et al. 2018, The Astrophysical Journal, 856, 124, doi: 10.3847/1538-4357/aab1f1

    2018 doi

  84. [92]

    K., Rahul, K

    Ramachandran, R., Meka, J. K., Rahul, K. K., et al. 2023, Icarus, 115896, doi: 10.1016/j.icarus.2023.115896

    2023

  85. [93]

    Rivkin, A. S. 2012, Icarus, 221, 744, doi: 10.1016/j.icarus.2012.08.042

    2012 doi

  86. [94]

    S., Thomas, C

    Rivkin, A. S., Thomas, C. A., Wong, I., et al. 2025, The Planetary Science Journal, 6, 9, doi: 10.3847/PSJ/ad944c

    2025 doi

  87. [95]

    L., de Le´ on, J., Licandro, J., et al

    Rizos, J. L., de Le´ on, J., Licandro, J., et al. 2019, Icarus, 328, 69, doi: 10.1016/j.icarus.2019.03.007

    2019 doi

  88. [96]

    1991, Journal of Geophysical Research: Planets, 96, 17535, doi: 10.1029/91JE01681

    Sack, N., Boring, J., Johnson, R., Baragiola, R., & Shi, M. 1991, Journal of Geophysical Research: Planets, 96, 17535, doi: 10.1029/91JE01681

    1991 doi

  89. [97]

    2018, Center),

    Schmitt, B., Bollard, P., Albert, D., et al. 2018, Center),

    2018

  90. [98]

    2018, The Astrophysical Journal Letters, 855, L26, doi: 10.3847/2041-8213/aab3dc

    Schonebeck, F. 2018, The Astrophysical Journal Letters, 855, L26, doi: 10.3847/2041-8213/aab3dc

    2018 doi

  91. [99]

    Sharkey, B. N. L., Rivkin, A. S., Cartwright, R. J., et al. 2025, JWST Reveals Varied Origins Between Jupiter’s Irregular Satellites, arXiv, doi: 10.48550/arXiv.2501.16484

    2025 doi arXiv

  92. [100]

    B., & Roush, T

    Singer, R. B., & Roush, T. L. 1985, Journal of Geophysical Research: Solid Earth, 90, 12434, doi: 10.1029/JB090iB14p12434

    1985 doi

  93. [101]

    R., & Calvin, W

    Spencer, J. R., & Calvin, W. M. 2002, The Astronomical Journal, 124, 3400, doi: 10.1086/344307

    2002 doi

  94. [102]

    R., Calvin, W

    Spencer, J. R., Calvin, W. M., & Person, M. J. 1995, Journal of Geophysical Research: Planets, 100, 19049, doi: 10.1029/95JE01503 36

    1995 doi

  95. [103]

    R., McEwen, A

    Spencer, J. R., McEwen, A. S., McGrath, M. A., et al. 1997, Icarus, 127, 221, doi: 10.1006/icar.1996.5670{}

    1997

  96. [104]

    2001, The NIST Chemistry WebBook: A chemical data resource on the internet, ed

    Talrose, V., Yermakov, A., Usov, A., et al. 2001, The NIST Chemistry WebBook: A chemical data resource on the internet, ed. P. J. Linstrom & W. G. Mallard, Vol. 46 (ACS Publications)

    2001

  97. [105]

    2006, The Astrophysical Journal, 644, L141, doi: 10.1086/505743

    Teolis, B., Loeffler, M., Raut, U., Fama, M., & Baragiola, R. 2006, The Astrophysical Journal, 644, L141, doi: 10.1086/505743

    2006 doi

  98. [106]

    2024, Nature Astronomy, 8, 82, doi: 10.1038/s41550-023-02107-5

    Tosi, F., Mura, A., Cofano, A., et al. 2024, Nature Astronomy, 8, 82, doi: 10.1038/s41550-023-02107-5

    2024 doi

  99. [107]

    K., Brown, M

    Trumbo, S. K., Brown, M. E., & Adams, D. 2021, The Planetary Science Journal, 2, 139, doi: 10.3847/PSJ/ac0cee

    2021 doi

  100. [108]

    K., Brown, M

    Trumbo, S. K., Brown, M. E., & Hand, K. P. 2019a, The Astronomical Journal, 158, 127, doi: 10.3847/1538-3881/ab380c —. 2019b, Science advances, 5, doi: 10.1126/sciadv.aaw7123 —. 2020, The Astronomical Journal, 160, 282, doi: 10.3847/1538-3881/abc34c

    2020 doi

  101. [109]

    K., Davis, M

    Trumbo, S. K., Davis, M. R., Cassese, B., & Brown, M. E. 2022a, The Planetary Science Journal, 3, 272, doi: 10.3847/PSJ/aca46d

    doi

  102. [110]

    K., Becker, T

    Trumbo, S. K., Becker, T. M., Brown, M. E., et al. 2022b, The Planetary Science Journal, 3, 27, doi: 10.3847/PSJ/ac4580

    doi

  103. [111]

    K., Brown, M

    Trumbo, S. K., Brown, M. E., Bockel´ ee-Morvan, D., et al. 2023, Science Advances, 9, doi: 10.1126/sciadv.adg3724

    2023 doi

  104. [112]

    G., Vuitton, V., Danger, G., et al

    Urso, R. G., Vuitton, V., Danger, G., et al. 2020, Astronomy & Astrophysics, 644, A115, doi: 10.1051/0004-6361/202039528 USGS Astrogeology Science Center. 2013, Callisto Galileo/Voyager global mosaic 1km, https://astrogeology. usgs.gov/search/map/Callisto/Voyager-Galileo/ Call...

    2020 doi

  105. [113]

    S., & Gaffey, M

    Vilas, F., Jarvis, K. S., & Gaffey, M. J. 1994, Icarus, 109, 274, doi: 10.1006/icar.1994.1093

    1994

  106. [114]

    2021, Nature Communications, 12, 6543, doi: 10.1038/s41467-021-26860-1

    Wakita, S., Johnson, B., Garrick-Bethell, I., et al. 2021, Nature Communications, 12, 6543, doi: 10.1038/s41467-021-26860-1

    2021 doi

  107. [115]

    L., Umurhan, O

    White, O. L., Umurhan, O. M., Moore, J. M., & Howard, A. D. 2016, Journal of Geophysical Research: Planets, 121, 21, doi: 10.1002/2015JE004846

    2016 doi

  108. [116]

    2019, The Astronomical Journal, 157, 161, doi: 10.3847/1538-3881/ab0e00

    Mahjoub, A. 2019, The Astronomical Journal, 157, 161, doi: 10.3847/1538-3881/ab0e00

    2019 doi

  109. [117]

    K., Brown, M

    Wu, P., Trumbo, S. K., Brown, M. E., & de Kleer, K. 2024, The Planetary Science Journal, 5, 220, doi: 10.3847/PSJ/ad7468

    2024 doi

  110. [118]

    2022, Optik, 265, 169522, doi: 10.1016/j.ijleo.2022.169522

    Zhou, X., Hu, P., Ma, C., Huang, S., & Sun, J. 2022, Optik, 265, 169522, doi: 10.1016/j.ijleo.2022.169522

    2022

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