Evidence for limited compositional and particle size variation on asteroid (101955) Bennu from thermal infrared spectroscopy - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Astronomy and Astrophysics - A&A Année : 2021

Evidence for limited compositional and particle size variation on asteroid (101955) Bennu from thermal infrared spectroscopy

V. Hamilton
P. Christensen
  • Fonction : Auteur
H. Kaplan
  • Fonction : Auteur
C. Haberle
  • Fonction : Auteur
A. Rogers
  • Fonction : Auteur
T. Glotch
  • Fonction : Auteur
L. Breitenfeld
  • Fonction : Auteur
C. Goodrich
  • Fonction : Auteur
D. Schrader
  • Fonction : Auteur
T. Mccoy
  • Fonction : Auteur
R. Hanna
  • Fonction : Auteur
A. Simon
  • Fonction : Auteur
J. Brucato
  • Fonction : Auteur
B. Clark
  • Fonction : Auteur
D. Lauretta
  • Fonction : Auteur

Résumé

Context. Asteroid (101955) Bennu is the target of NASA’s Origins, Spectral Interpretation, Resource Identification, and Security–Regolith Explorer (OSIRIS-REx) mission. The spacecraft’s instruments have characterized Bennu at global and local scales to select a sampling site and provide context for the sample that will be returned to Earth. These observations include thermal infrared spectral characterization by the OSIRIS-REx Thermal Emission Spectrometer (OTES). Aims. To understand the degree of compositional and particle size variation on Bennu, and thereby predict the nature of the returned sample, we studied OTES spectra, which are diagnostic of these properties. Methods. We created and mapped spectral indices and compared them with the distribution of geomorphic features. Comparison to laboratory spectra of aqueously altered carbonaceous chondrites constrains the amount of compositional variability that is observable. Results. The OTES spectra exhibit two end-member shapes (or types), and compositional variability appears limited at the spatial resolution of the observations. The global distribution of these spectral types corresponds with the locations of regions composed of (i) large, dark, relatively rough boulders and (ii) relatively smooth regions lacking large boulders. Conclusions. The two spectral types appear to be diagnostic primarily of particle size variations, with contributions from other properties. The spectra resemble experimental data of solid substrates with very thin accumulations (a few to tens of microns) of fine particles (<~65–100 μm). The dustier surfaces commonly correspond with rougher rocks that may produce and/or act as traps for the particles. Anhydrous silicates are limited in abundance, and the bulk mineralogy is consistent with the most aqueously altered carbonaceous chondrites. We expect the returned samples to include these physical and mineralogical characteristics.
Fichier principal
Vignette du fichier
aa39728-20.pdf (12.72 Mo) Télécharger le fichier
Origine Fichiers éditeurs autorisés sur une archive ouverte

Dates et versions

hal-04490173 , version 1 (10-03-2024)

Identifiants

Citer

V. Hamilton, P. Christensen, H. Kaplan, C. Haberle, A. Rogers, et al.. Evidence for limited compositional and particle size variation on asteroid (101955) Bennu from thermal infrared spectroscopy. Astronomy and Astrophysics - A&A, 2021, 650 (5), pp.A120. ⟨10.1051/0004-6361/202039728⟩. ⟨hal-04490173⟩
13 Consultations
0 Téléchargements

Altmetric

Partager

Gmail Mastodon Facebook X LinkedIn More