Introduction to the Special Issue : Exploration of the Activity of Asteroid (101955) Bennu

©2020. The Authors..

Near-Earth asteroid (101955) Bennu is an active asteroid experiencing mass loss. The activity manifests itself in the form of ejection events emitting up to hundreds of millimeter- to centimeter-scale particles. The Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer spacecraft monitored particle activity for a 10-month period that included Bennu's perihelion and aphelion. Novel and classical methods were utilized to detect the particles and characterize their orbital and physical properties. Roughly 30% of the observed particle mass escaped to heliocentric orbit. A majority of particles fell back onto the surface of Bennu after ejection, with the longest-lived particle surviving for 6 days on a temporary orbit. Particle ejection events appear to preferentially take place in the afternoon and evening and from low latitudes, although they can occur at any time or latitude. The reaccumulation of material is biased toward low latitudes resulting in the possible in-fill of craters and growth of Bennu's equatorial bulge. Of the potential mechanisms behind this activity that were investigated in focused studies, meteoroid impacts, thermal fracturing, and ricochet-but not water ice sublimation-were found to be consistent with observations. While phyllosilicate dehydration was not investigated with a focused study, it remains a possible mechanism. These mechanisms are not unique to Bennu, suggesting that many near-Earth asteroids may exhibit activity that has gone undetected thus far. Spacecraft missions with wide-field imagers are encouraged to further characterize this phenomenon.

Medienart:

E-Artikel

Erscheinungsjahr:

2020

Erschienen:

2020

Enthalten in:

Zur Gesamtaufnahme - volume:125

Enthalten in:

Journal of geophysical research. Planets - 125(2020), 9 vom: 06. Sept., Seite e2020JE006549

Sprache:

Englisch

Beteiligte Personen:

Hergenrother, C W [VerfasserIn]
Adam, C D [VerfasserIn]
Chesley, S R [VerfasserIn]
Lauretta, D S [VerfasserIn]

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Journal Article

Anmerkungen:

Date Revised 12.11.2023

published: Print-Electronic

Citation Status PubMed-not-MEDLINE

doi:

10.1029/2020JE006549

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM316125466