Ammonia on Ceres

Abstract

Even before the arrival of the Dawn spacecraft, Ceres attracted attention due to its infrared spectral properties, which were distinct from most other asteroids (see Chapter 1). First speculated based on telescopic data (King et al., Reference King, Clark, Calvin, Sherman and Brown1992), subsequent data from the Dawn spacecraft confirmed the presence of ammonium on Ceres. Ammonium has been identified within near-ubiquitous dark materials, and in salts in a few localized bright faculae in the interiors of craters, as we describe further in this chapter (De Sanctis et al., Reference De Sanctis, Frigeri and Ammannito2015, Reference De Sanctis, Raponi and Ammannito2016; Ammannito et al., Reference Ammannito, DeSanctis and Ciarniello2016; Raponi et al., Reference Raponi, De Sanctis and Carrozzo2019; see also Chapter 7).