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Discovery of the first olivine-dominated A-type asteroid family

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posted on 2024-05-01, 14:45 authored by M Galinier, M Delbo, C Avdellidou, L Galluccio
The classical theory of differentiation states that due to the heat generated by the decay of radioactive elements, some asteroids form an iron core, an olivine-rich mantle, and a crust. The collisional breakup of these differentiated bodies is expected to lead to exposed mantle fragments, creating families of newly-formed asteroids. Among these new objects, some are expected to show an olivine-rich composition in spectroscopic observations. However, several years of spectrophotometric surveys have led to the conclusion that olivine-rich asteroids are rare in the asteroid main belt, and no significant concentration of olivine-rich bodies in any asteroid family has been detected to date. Using ESA’s Gaia DR3 reflectance spectra, we show that the family (36256) 1999 XT17 presents a prominence of objects that are likely to present an olivine-rich composition (A-type spectroscopic class). If S-complex asteroids as the second most prominent spectroscopic class in the family are real family members, then arguably the 1999 XT17 family has originated from the break-up of a partially differentiated parent body. Alternatively, if the S-complex asteroids are interlopers, then the 1999 XT17 family could have originated from the breakup of an olivine-rich body. This body could have been part of the mantle of a differentiated planetesimal, which may have broken up in a different region of the Solar System, and one of its fragments (i.e. the parent body of the 1999 XT17 family) could have been dynamically implanted in the main belt.

History

Author affiliation

College of Science & Engineering/Physics & Astronomy

Version

  • VoR (Version of Record)

Published in

Astronomy & Astrophysics

Volume

683

Pagination

L3

Publisher

EDP Sciences

issn

0004-6361

eissn

1432-0746

Copyright date

2024

Available date

2024-05-01

Language

en

Deposited by

Dr Chrysa Avdellidou

Deposit date

2024-04-30

Rights Retention Statement

  • No

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