Global geologic map of asteroid (101955) Bennu indicates heterogeneous resurfacing in the past 500,000 years

Jawin, E. R.; McCoy, Timothy J.; Walsh, K. J.; Connolly, H. C.; Ballouz, Ronald-Louis; Ryan, A. J.; Kaplan, H. H.; Pajola, M.; Hamilton, Victoria E.; Barnouin, O. S.; Emery, Joshua P.; Rozitis, B.; DellaGiustina, D. N.; Daly, M. G.; Bennett, C. A.; Golish, D. R.; Perry, M. E.; Daly, R. T.; Bierhaus, E. B.; Nolan, M. C.; Enos, H.; Лауретта, Д. С.

doi:10.1016/j.icarus.2022.114992

Cited by 20 publications

(13 citation statements)

References 56 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We construct a polyhedral shape of the given rubble-pile model to calculate based on the alpha-shape algorithm 68 . By varying the alpha radius α from 10 to 50, incremented by 10, we obtained α = 30 for best fitting the surface slope distribution of Bennu 69 (Supplementary Fig. 5 ).…”

Section: Methodsmentioning

confidence: 99%

Inferring interiors and structural history of top-shaped asteroids from external properties of asteroid (101955) Bennu

et al. 2022

View full text Add to dashboard Cite

Asteroid interiors play a key role in our understanding of asteroid formation and evolution. As no direct interior probing has been done yet, characterisation of asteroids’ interiors relies on interpretations of external properties. Here we show, by numerical simulations, that the top-shaped rubble-pile asteroid (101955) Bennu’s geophysical response to spinup is highly sensitive to its material strength. This allows us to infer Bennu’s interior properties and provide general implications for top-shaped rubble piles’ structural evolution. We find that low-cohesion (≲0.78 Pa at surface and ≲1.3 Pa inside) and low-friction (friction angle ≲ 35∘) structures with several high-cohesion internal zones can consistently account for all the known geophysical characteristics of Bennu and explain the absence of moons. Furthermore, we reveal the underlying mechanisms that lead to different failure behaviours and identify the reconfiguration pathways of top-shaped asteroids as functions of their structural properties that either facilitate or prevent the formation of moons.

show abstract

Section: Methodsmentioning

confidence: 99%

Inferring interiors and structural history of top-shaped asteroids from external properties of asteroid (101955) Bennu

et al. 2022

View full text Add to dashboard Cite

show abstract

“…The creep processes is removing over‐steepened crater rims upslope, and filling crater interiors downslope, thereby removing them. The cumulative effects of creep on putatively younger, intermediate‐sized (10–30 m in diameter) craters appears to be small (Bierhaus et al., 2022; Jawin et al., 2022). This may be because creep is a slow but long‐lived.…”

Section: Terrace Formation On Bennu: Synthesis and Conclusionmentioning

confidence: 99%

“…The cumulative effects of creep on putatively younger, intermediate-sized (10-30 m in diameter) craters appears to be small (Bierhaus et al, 2022;Jawin et al, 2022). This may be because creep is a slow but long-lived.…”

Section: Terrace Formation On Bennu: Synthesis and Conclusionmentioning

confidence: 99%

The Formation of Terraces on Asteroid (101955) Bennu

et al. 2022

View full text Add to dashboard Cite

show abstract

“…Finally, it is expected that the shape of the core will affect landslide outcomes. An investigation into this, accompanied with comparisons with geological observations of Bennu [31], may help in constraining the core’s shape of Bennu.…”

Section: Discussionmentioning

confidence: 99%

“…A noticeable feature of asteroids Bennu and Ryugu (figure 1) is their equatorial ridge [31][32][33], which was also observed on other top-shaped asteroids like 1999 KW4 Alpha [34], Didymos A [35], and 2008 EV5 [36]. The formation of a top shape, and the equatorial ridge and its features have been sought to be explained in various ways [15], in particular: gravitational reaccumulation following a cataclysmic disruption event [37], debris accretion onto a rotating spherical core [38], rotational disruption of complete rubble piles [39], emplacement of ejecta from low-and mid-latitude craters [40], and regolith movement on the surface of a solid core driven by high spin rates [41][42][43][44] or by seismic shaking [45].…”

Section: Introductionmentioning

confidence: 99%

Regolith flow on top-shaped asteroids

2022

View full text Add to dashboard Cite

We develop a continuum framework of regolith flow on asteroids. We focus on top-shaped asteroids that may be taken as consisting of regolith lying on a solid core. Depth-averaging is employed to model the regolith flow, and effects due to the asteroid’s rotation and its complex gravity field are retained. Angular momentum conservation is invoked to couple regolith flow to the asteroid’s changing shape and spin. This framework is first used to explore the equilibrium of regolith as a function of its friction, and the asteroid’s shape and spin rate. Next, we study regolith flow on top-shaped spinning asteroids and find conditions for the regolith’s shedding or deposition. We also discuss how the regolith’s flow and the asteroid’s spin influence each other. Finally, as an application, we propose and investigate the following evolution history of Bennu: a fast spinning Bennu was slowed down by multiple, impact-induced global landslides to its present spin state. Regolith was shed if the spin was higher than a critical rate. Once the spin rate fell below this critical value, regolith flow from higher latitudes began depositing regolith at its equator, giving Bennu its distinctive shape.

show abstract

Global geologic map of asteroid (101955) Bennu indicates heterogeneous resurfacing in the past 500,000 years

Cited by 20 publications

References 56 publications

Inferring interiors and structural history of top-shaped asteroids from external properties of asteroid (101955) Bennu

Inferring interiors and structural history of top-shaped asteroids from external properties of asteroid (101955) Bennu

The Formation of Terraces on Asteroid (101955) Bennu

Regolith flow on top-shaped asteroids

Contact Info

Product

Resources

About