Disk-resolved photometric modeling and properties of asteroid (101955) Bennu

• Published in: Icarus (New York, N.Y. 1962) N.Y. 1962), 2021-03, Vol.357, p.113724, Article 113724
• Main Authors: Golish, D.R., DellaGiustina, D.N., Li, J.-Y., Clark, B.E., Zou, X.-D., Smith, P.H., Rizos, J.L., Hasselmann, P.H., Bennett, C.A., Fornasier, S., Ballouz, R.-L., Drouet d'Aubigny, C., Rizk, B., Daly, M.G., Barnouin, O.S., Philpott, L., Al Asad, M.M., Seabrook, J.A., Johnson, C.L., Lauretta, D.S.
• Format: Article
• Language: English
• Subjects: Asteroids; Image processing; Photometry; Sciences of the Universe; Spectrophotometry
• ISSN: 0019-1035; 1090-2643
• DOI: 10.1016/j.icarus.2020.113724

OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, and Security–Regolith Explorer) is a NASA mission to return a sample of asteroid (101955) Bennu. Photometric modeling of Bennu's surface is a key element of both sample site characterization and our broader scientific understanding of the asteroid. Bennu's heterogeneous surface presents substantial variation in reflectance and produces a scattered dataset that poses a challenge to photometric modeling. We show that the resolution of the shape model with which we calculate photometric angles strongly affects the accuracy of the analysis, as well as the efficacy of subsequent photometric corrections. We use global imaging data to fit empirical photometric models of the surface. These models represent the average behavior of Bennu's surface and can be used beyond this work to photometrically correct panchromatic and color basemaps of Bennu and perform albedo analyses of individual features on Bennu's surface. Bennu's global photometry reveals a moderate opposition effect and detectable phase reddening, both of which suggest a macroscopically rough surface, which is confirmed by centimeter-scale images of the asteroid. •The OSIRIS-REx spacecraft globally imaged asteroid Bennu.•Bennu's extremely rough terrain poses challenges to photometric modeling.•The resolution of the shape model affects photometric modeling and correction accuracy.•Bennu's surface shows evidence of moderate phase reddening.•A shallow, broad opposition surge is consistent with Bennu's dark surface.