Detection of local H
            <sub>2</sub>
            O exposed at the surface of Ceres

Combe, J.; McCord, T. B.; Tosi, F.; Ammannito, E.; Carrozzo, F. G.; Sanctis, M. C. De; Raponi, A.; Byrne, Shane; Landis, M. E.; Hughson, K.; Raymond, C. A.; Russell, C. T.

doi:10.1126/science.aaf3010

Cited by 133 publications

(126 citation statements)

References 47 publications

Supporting

Mentioning

117

Contrasting

Order By: Relevance

“…The Oxo BS involves bright material on the crater wall and in ejecta, corresponding to a fresh unit probably formed during the youngest Cerean period (Hughson et al, 2016). …”

Section: Accepted Manuscriptmentioning

confidence: 99%

Compositional differences among Bright Spots on the Ceres surface

Palomba¹,

Longobardo²,

Sanctis³

et al. 2019

Icarus

View full text Add to dashboard Cite

“…The Oxo BS involves bright material on the crater wall and in ejecta, corresponding to a fresh unit probably formed during the youngest Cerean period (Hughson et al, 2016). …”

Section: Accepted Manuscriptmentioning

confidence: 99%

Compositional differences among Bright Spots on the Ceres surface

Palomba¹,

Longobardo²,

Sanctis³

et al. 2019

Icarus

View full text Add to dashboard Cite

“…The surface shows evidence for aqueous alteration; ammoniated phyllosilicates are widespread . Small, isolated patches of water ice lie exposed on the surface (Combe et al, 2016). Data for a third instrument, a gamma ray and neutron detector (GRaND) are best acquired in the close proximity to the surface that is attained in the low altitude orbit at the end of the Ceres mission.…”

Section: Introductionmentioning

confidence: 99%

Resolved spectrophotometric properties of the Ceres surface from Dawn Framing Camera images

Schröder

Mottola

Carsenty

et al. 2017

Icarus

100

View full text Add to dashboard Cite

We present a global spectrophotometric characterization of the Ceres surface using Dawn Framing Camera (FC) images. We identify the photometric model that yields the best results for photometrically correcting images. Corrected FC images acquired on approach to Ceres were assembled into global maps of albedo and color. Generally, albedo and color variations on Ceres are muted. The albedo map is dominated by a large, circular feature in Vendimia Planitia, known from HST images (Li et al., 2006), and dotted by smaller bright features mostly associated with fresh-looking craters. The dominant color variation over the surface is represented by the presence of "blue" material in and around such craters, which has a negative spectral slope over the visible wavelength range when compared to average terrain. We also mapped variations of the phase curve by employing an exponential photometric model, a technique previously applied to asteroid Vesta . The surface of Ceres scatters light differently from Vesta in the sense that the ejecta of several fresh-looking craters may be physically smooth rather than rough. High albedo, blue color, and physical smoothness all appear to be indicators of youth. The blue color may result from the desiccation of ejected material that is similar to the phyllosilicates/water ice mixtures in the experiments of Poch et al. (2016). The physical smoothness of some blue terrains would be consistent with an initially liquid condition, perhaps as a consequence of impact melting of subsurface water ice. We find red terrain (positive spectral slope) near Ernutet crater, where De Sanctis et al. (2017) detected organic material. The spectrophotometric properties of the large Vendimia Planitia feature suggest it is a palimpsest, consistent with the Marchi et al. (2016) impact basin hypothesis. The central bright area in Occator crater, Cerealia Facula, is the brightest on Ceres with an average visual normal albedo of about 0.6 at a resolution of 1.3 km per pixel (six times Ceres average). The albedo of fresh, bright material seen inside this area in the highest resolution images (35 m per pixel) is probably around unity. Cerealia Facula has an unusually steep phase function, which may be due to unresolved topography, high surface roughness, or large average particle size. It has a strongly red spectrum whereas the neighboring, less-bright, Vinalia Faculae are neutral in color. We find no evidence for a diurnal ground fog-type haze in Occator as described by Nathues et al. (2015). We can neither reproduce their findings using the same images, nor confirm them using higher resolution images. FC images have not yet offered direct evidence for present sublimation in Occator.

show abstract

“…Recent observations from Dawn and gravity data (Park et al 2016) point instead to a high-density outer shell dominated by rocky material (Castillo-Rogez et al 2016). Spectral modeling of surface spectra acquired by the Dawn mission shows widespread ammoniated phyllosilicates (De Sanctis et al 2015;Ammannito et al 2016) and abundant carbonate deposits in localized areas due to aqueous alteration as well as small spots of water ice in the northern hemisphere (Combe et al 2016). A&A 598, A130 (2017) The Dawn spacecraft (Russell & Raymond 2011) carries three instruments: the Framing Camera (FC, Sierks et al 2011), the Visible and Infrared spectrometer (VIR, De Sanctis et al 2011), and the Gamma Ray and Neutron Detector (GRAND, Prettyman et al 2011).…”

Section: Introduction and Rationalementioning

confidence: 99%

Spectrophotometric properties of dwarf planet Ceres from the VIR spectrometer on board the Dawn mission

Ciarniello

Sanctis

Ammannito

et al. 2017

A&A

View full text Add to dashboard Cite

Aims. We present a study of the spectrophotometric properties of dwarf planet Ceres in the visual-to-infrared (VIS-IR) spectral range by means of hyper-spectral images acquired by the VIR imaging spectrometer on board the NASA Dawn mission. Methods. Disk-resolved observations with a phase angle within the 7• < α < 132• interval were used to characterize Ceres' phase curve in the 0.465-4.05 µm spectral range. Hapke's model was applied to perform the photometric correction of the dataset to standard observation geometry at VIS-IR wavelength, allowing us to produce albedo and color maps of the surface. The V-band magnitude phase function of Ceres has been computed from disk-resolved images and fitted with both the classical linear model and H-G formalism.Results. The single-scattering albedo and the asymmetry parameter at 0.55 µm are w = 0.14 ± 0.02 and ξ = −0.11 ± 0.08, respectively (two-lobe Henyey-Greenstein phase function); at the same wavelength, Ceres' geometric albedo as derived from our modeling is 0.094 ± 0.007; the roughness parameter isθ = 29• ± 6• . Albedo maps indicate small variability on a global scale with an average reflectance at standard geometry of 0.034 ± 0.003. Nonetheless, isolated areas such as the Occator bright spots, Haulani, and Oxo show an albedo much higher than average. We measure a significant spectral phase reddening, and the average spectral slope of Ceres' surface after photometric correction is 1.1% kÅ • gives H = 3.14 ± 0.04 and G = 0.10 ± 0.04, while the classical linear model provides V(1, 1, 0 • ) = 3.48 ± 0.03 and β = 0.036 ± 0.002. The comparison of our results with spectrophotometric properties of other minor bodies indicates that Ceres has a less back-scattering phase function and a slightly higher albedo than comets and C-type objects. However, the latter represents the closest match in the usual asteroid taxonomy.

show abstract

Detection of local H ₂ O exposed at the surface of Ceres

Cited by 133 publications

References 47 publications

Compositional differences among Bright Spots on the Ceres surface

Compositional differences among Bright Spots on the Ceres surface

Resolved spectrophotometric properties of the Ceres surface from Dawn Framing Camera images

Spectrophotometric properties of dwarf planet Ceres from the VIR spectrometer on board the Dawn mission

Contact Info

Product

Resources

About

Detection of local H 2 O exposed at the surface of Ceres

Cited by 133 publications

References 47 publications

Compositional differences among Bright Spots on the Ceres surface

Compositional differences among Bright Spots on the Ceres surface

Resolved spectrophotometric properties of the Ceres surface from Dawn Framing Camera images

Spectrophotometric properties of dwarf planet Ceres from the VIR spectrometer on board the Dawn mission

Contact Info

Product

Resources

About

Detection of local H ₂ O exposed at the surface of Ceres