Q-type asteroids: Possibility of non-fresh weathered surfaces
Sunao Hasegawa, Takahiro Hiroi, Katsuhito Ohtsuka, Masateru Ishiguro, Daisuke Kuroda, Takashi Ito, Sho Sasaki
(Submitted on 18 Jul 2019)
Itokawa particles, which are the recovered samples from the S-complex asteroid 25143 Itokawa by the Hayabusa spacecraft, demonstrate that S-complex asteroids are parent bodies of ordinary chondrite meteorites. Furthermore, they clarify that the space weathering age of the Itokawa surface is of the order of several thousand years. Traditionally, Q-type asteroids have been considered fresh-surfaced. However, as the space weathering timescale is approximately three orders of magnitude lesser than the conventionally considered age, the previously proposed formation mechanisms of Q-type asteroids cannot sufficiently explain the surface refreshening. In this study, we propose a new hypothesis on the surface state of Q-type asteroids: Q-type asteroids have a non-fresh weathered surface with a paucity of fine particles. For verifying this hypothesis, laboratory experiments on the space weathering of ordinary chondrites are performed. Based on the results of these experiments, we found that large (more than 100 {\mu}m) ordinary chondritic particles with space weathering exhibit spectra consistent with Q-type asteroids.
Comments: 14 pages, 5 figures, and 1 table, accepted for publication in PASJ
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:1907.08266 [astro-ph.EP] (or arXiv:1907.08266v1 [astro-ph.EP] for this version)
Submission history
From: Sunao Hasegawa
[v1] Thu, 18 Jul 2019 20:10:53 UTC (1,309 KB)
