Insights into Ceres's evolution from surface composition

Castillo‐Rogez, Julie; Neveu, Marc; McSween, H. Y.; Fu, R. R.; Toplis, Michael J.; Prettyman, T. H.

doi:10.1111/maps.13181

Cited by 88 publications

(119 citation statements)

References 92 publications

(183 reference statements)

Supporting

Mentioning

111

Contrasting

Order By: Relevance

“…While we recommend additional measurements of Hygiea and Interamnia to characterize any surface variation, it appears that both objects have areas with Pallas‐type and non‐Pallas‐type spectra. Models of Ceres' interior suggest that there may be a hydrated silicate layer beginning at a depth of ~50 km below a low‐density clay/clathrate layer (Castillo‐Rogez et al, ; King et al, ). If Hygiea and Interamnia also have compositional layers, it is possible that Hygiea had its interior exposed in only a few places, leading to a mostly Ceres‐type spectrum with a few Pallas‐type areas, while Interamnia had much of its original surface removed save for a few small regions.…”

Section: Analysis and Resultsmentioning

confidence: 99%

Infrared Spectroscopy of Large, Low‐Albedo Asteroids: Are Ceres and Themis Archetypes or Outliers?

2019

View full text Add to dashboard Cite

Low‐albedo, hydrated objects dominate the list of the largest asteroids. These objects have varied spectral shapes in the 3‐μm region, where diagnostic absorptions due to volatile species are found. Dawn's visit to Ceres has extended the view shaped by ground‐based observing and shown that world to be a complex one, potentially still experiencing geological activity. We present 33 observations from 2.2 to 4.0 μm of eight large (D > 200 km) asteroids from the C spectral complex, with spectra inconsistent with the hydrated minerals we see in meteorites. We characterize their absorption band characteristics via polynomial and Gaussian fits to test their spectral similarity to Ceres, the asteroid 24 Themis (thought to be covered in ice frost), and the asteroid 51 Nemausa (spectrally similar to the CM meteorites). We confirm most of the observations are inconsistent with what is seen in meteorites and require additional absorbers. We find clusters in band centers that correspond to Ceres‐ and Themis‐like spectra, but no hiatus in the distribution suitable for use to simply distinguish between them. We also find a range of band centers in the spectra that approaches what is seen on Comet 67P. Finally, variation is seen between observations for some objects, with the variation on 324 Bamberga consistent with hemispheric‐level difference in composition. Given the ubiquity of objects with 3‐μm spectra unlike what we see in meteorites, and the similarity of those spectra to the published spectra of Ceres and Themis, these objects appear much more to be archetypes than outliers.

show abstract

Section: Analysis and Resultsmentioning

confidence: 99%

Infrared Spectroscopy of Large, Low‐Albedo Asteroids: Are Ceres and Themis Archetypes or Outliers?

2019

View full text Add to dashboard Cite

show abstract

“…The amount of remaining liquid versus temperature for the mix of salts predicted by Castillo-Rogez et al (2018) is presented in Figure 3a. The remaining liquid fraction represents ≤2% of the original ocean for temperatures below ∼248 K and ≤1% below ∼244 K. At 220 K, only 0.4% of the original ocean remains.…”

Section: Representative Interior Evolution Models Consistent With Dawmentioning

confidence: 99%

Conditions for the Long‐Term Preservation of a Deep Brine Reservoir in Ceres

Castillo‐Rogez

Hesse

Formisano

et al. 2019

Geophysical Research Letters

Self Cite

View full text Add to dashboard Cite

We propose a new internal evolution model for the dwarf planet Ceres matching the constraints on Ceres' present internal state from the Dawn mission observations. We assume an interior differentiated into a volatile‐dominated crust and rocky mantle, and with remnant brines in the mantle, all consistent with inferences from the Dawn geophysical observations. Simulations indicate Ceres should preserve a warm crust until present if the crust is rich in clathrate hydrates. The temperature computed at the base of the crust exceeds 220 K for a broad range of conditions, allowing for the preservation of a small amount of brines at the base of the crust. However, a temperature ≥250 K, for which at least 1 wt.% sodium carbonate gets in solution requires a crustal abundance of clathrate hydrates greater than 55 vol.%, a situation possible for a narrow set of evolutionary scenarios.

show abstract

“…The structure suggested by recent modeling is at least partially differentiated and has multiple layers: a thin crust of dirty ice (rock and salts), a frozen ocean, a liquid basal water layer, a hydrated rocky outer core and a dry rocky inner core (e.g., . This is, however, challenged by further interior models that match an only weakly differentiated structure with observations (Castillo-Rogez et al 2016, 2019 or infer no differentiation at all (Zolotov 2009(Zolotov , 2020, and by density constraints derived from gravity data that argue against silicate dehydration in the interior (Ermakov et al 2017).…”

Section: Introductionmentioning

confidence: 99%

Ceres’ partial differentiation: undifferentiated crust mixing with a water-rich mantle

Neumann

Jaumann

Castillo‐Rogez

et al. 2020

A&A

View full text Add to dashboard Cite

Aims. We model thermal evolution and water-rock differentiation of small ice-rock objects that accreted at different heliocentric distances, while also considering migration into the asteroid belt for Ceres. We investigate how water-rock separation and various cooling processes influence Ceres’ structure and its thermal conditions at present. We also draw conclusions about the presence of liquids and the possibility of cryovolcanism. Methods. We calculated energy balance in bodies heated by radioactive decay and compaction-driven water-rock separation in a three-component dust-water/ice-empty pores mixture, while also taking into consideration second-order processes, such as accretional heating, hydrothermal circulation, and ocean or ice convection. Calculations were performed for varying accretion duration, final size, surface temperature, and dust/ice ratio to survey the range of possible internal states for precursors of Ceres. Subsequently, the evolution of Ceres was considered in five sets of simulated models, covering different accretion and evolution orbits and dust/ice ratios. Results. We find that Ceres’ precursors in the inner solar system could have been both wet and dry, while in the Kuiper belt, they retain the bulk of their water content. For plausible accretion scenarios, a thick primordial crust may be retained over several Gyr, following a slow differentiation within a few hundreds of Myr, assuming an absence of destabilizing impacts. The resulting thermal conditions at present allow for various salt solutions at depths of ≲10 km. The warmest present subsurface is obtained for an accretion in the Kuiper belt and migration to the present orbit. Conclusions. Our results indicate that Ceres’ material could have been aqueously altered on small precursors. The modeled structure of Ceres suggests that a liquid layer could still be present between the crust and the core, which is consistent with Dawn observations and, thus, suggests accretion in the Kuiper belt. While the crust stability calculations indicate crust retention, the convection analysis and interior evolution imply that the crust could still be evolving.

show abstract

Insights into Ceres's evolution from surface composition

Cited by 88 publications

References 92 publications

Infrared Spectroscopy of Large, Low‐Albedo Asteroids: Are Ceres and Themis Archetypes or Outliers?

Infrared Spectroscopy of Large, Low‐Albedo Asteroids: Are Ceres and Themis Archetypes or Outliers?

Conditions for the Long‐Term Preservation of a Deep Brine Reservoir in Ceres

Ceres’ partial differentiation: undifferentiated crust mixing with a water-rich mantle

Contact Info

Product

Resources

About