http://vigarano.ep.sci.hokudai.ac.jp/shogo/adv_geochemistry2015/Week%204/Background%20reading/Bus%20and%20Binzel%202002.pdf

Phase II of the Small Main-Belt Asteroid Spectroscopic Survey: A Feature-Based Taxonomy

Density of asteroids

The composition and origin of the C, P, and D asteroids: Water as a tracer of thermal evolution in the outer belt

[1] We modeled several thermal evolution scenarios for Ceres to explore the nature of large, wet protoplanets and to predict current-day evidence that might be found by close inspection, such as by the Dawn mission. The density for Ceres is near 2.1, suggesting a water content between 17% and 27% by mass. Short- and long-lived radioactive nuclide heating is considered. Even if only long-lived radionuclide heating is assumed, the water ice in Ceres melts quickly and a water mantle forms, but an approximately 10-km crust does not melt. The circulating warm water would alter the silicates. As heat is lost by conduction through the frozen crust, water begins to freeze out at the base of the crust. Solid-state convection begins and transports more heat as well as perhaps material dissolved or entrained in the water to or near the surface. Ceres' water layer eventually (but perhaps not entirely) freezes, forming a layered density structure with perhaps some liquid water remaining today. Our differentiated models are in agreement with the recently measured difference between the equatorial and polar radii. We find that Ceres' existence and evolution depend critically on it containing water at formation, and this depends strongly on the combination of when it accreted and the amount of 26Al present in the pre-Ceres ∼1-km-sized objects; slightly more 26Al or earlier accretion produces a dry Vesta-like object. Melting and freezing plus mineralization would lead to several dimensional changes over time, creating topographic features, zones of weakness, and perhaps disruptions in the crust.

https://hal.archives-ouvertes.fr/hal-00116029/document

Ceres: Evolution and current state

https://www.uni-muenster.de/imperia/md/content/planetology/lectures/ss2015/143897-hottopics/castillo-rogez_and_mccord_2010.pdf

Ceres’ evolution and present state constrained by shape data

An absorption feature centred near 3.0 microns has been discovered in the infrared spectrum of asteroid 1 Ceres. This spectrum has been compared with laboratory spectra of meteorites and shows great similarity to the spectra of type II carbonaceous chondrites. By analogy this suggests the presence of about 10-15 per cent water in the form of water of hydration on the surface of Ceres. This is the first evidence of water in the surface material of an asteroid.

Asteroid 1 Ceres: evidence for water of hydration.

Observations made by the Infrared Astronomical Satellite (IRAS) during 1983 constitute the largest, most complete, and least biased of the asteroid surveys to date. A total of 1811 asteroids and 25 comets with known orbits were measured. Thermal flux densities at 12, 25, 60, and 100 microns, as well as (in the case of asteroids) their derived radiometric albedos and diameters have been compiled in the IRAS Asteroid and Comet Survey. Useful low-resolution spectra were obtained for 47 numbered asteroids. There is evidence in the IRAS data base for a large population of asteroids with unknown orbits. The methods of observation are outlined. The survey strategy and the data reduction are discussed. The rationale is given for the various IRAS asteroid and comet data products. Some directions for future research using IRAS data are suggested.

The IRAS asteroid and comet survey

Anomalous averaged infrared brightness temperatures of the Galilean satellites of Jupiter reported by Gross (1975) are rejected as falsely conceived and lacking physical reality. It is argued that the calculations of equilibrium temperatures should be corrected, whereupon predictions would be in satisfactory agreement with observations, in conformity with the radiometric method of determining the diameters of asteroids and satellites. The IR irradiance and the related disk-averaged brightness temperature for the spectral band are recommended as more relevant. Attention is drawn to some interesting discrepancies between calculated and observed temperatures of the Jovian satellites which merit further investigation.

https://science.sciencemag.org/content/sci/195/4273/92.full.pdf

Larry A. Lebofsky

Papers

Asteroid 1 Ceres: evidence for water of hydration.

The IRAS asteroid and comet survey

Galilean Satellites: Anomalous Temperatures Disputed