Bibcode
Campins, Humberto; Pinilla-Alonso, Noemi; de Leon, Julia; Morate, David
Bibliographical reference
American Astronomical Society, DPS meeting #50, id.508.04
Advertised on:
10
2018
Citations
0
Refereed citations
0
Description
Two sample-return missions, OSIRIS-REx and Hayabusa 2, have just arrived
at primitive near-Earth asteroids (NEAs) (101955) Bennu and (162173)
Ryugu, and it is of interest to predict the effects of space weathering
on their surfaces. Most spacecraft-accessible NEAs originate in the
inner asteroid belt, and these two sample-return targets most likely
originated in the Polana asteroid family (e.g., Campins et al. 2018 and
references therein). Spectroscopic studies of primitive inner-belt
families offer a preview of the properties expected in the NEAs they
produce. So far, primitive asteroids in the inner-belt fall into at
least two spectral groups. The first group includes the Polana, Eulalia
and Clarissa families, which show considerable spectral homogeneity and
no 0.7-μm hydration feature. In contrast, the Erigone and Sulamitis
families are spectrally diverse and most of their members show clear
0.7-μm hydration features (e.g., Pinilla-Alonso et al. 2017; Morate
et al. 2018). The Clarissa family is considerable younger than the
Polana family, at less than 100 million years versus approximately 2000
million years, respectively (Nesvorný et al. 2015), and there are
subtle yet significant spectral differences between these two families.
These differences are consistent with the space weathering trend
suggested by Lantz et al. (2015, 2017 and 2018). This agreement between
observations of inner-belt families and laboratory simulations of space
weathering has testable implications for Bennu and Ryugu: older terrains
would be expected to be bluer than younger surfaces (Campins et al.
2018; de León et al. 2018).