Comets and Asteroids

Optical Spectropolarimetry Of Large C-complex Asteroids: Polarimetric Evidence For Heterogeneous Surface Compositions

By Keith Cowing
Status Report
astro-ph.EP
July 31, 2023
Filed under , , , , ,
Optical Spectropolarimetry Of Large C-complex Asteroids: Polarimetric Evidence For Heterogeneous Surface Compositions
Orbital distributions of 12 C-complex asteroids observed with VLT/FORS2 in spectropolarimetry Background grey dots are numbered main-belt asteroids that are quoted from JPL Small-Body Database Query (https://ssd.jpl.nasa.gov/ tools/sbdb_query.html). Symbols in the highlighted color are proportional to the size of asteroids. Vertical lines at different heliocentric distances indicate the most important mean-motion resonances with Jupiter. — astro-ph.EP

This study presents the first optical spectropolarimetric study of large C-complex asteroids. A total of 64 C-complex asteroids of different subclasses are analyzed using archival polarimetric and reflectance data to refine the link between polarimetric parameters and surface properties of the asteroids.

We find a consistent difference in the polarization spectra between asteroids containing phyllosilicates and those without, which correlates with the overall morphology of the reflectance spectrum. They exhibit broad similarities in polarization-phase curves; nonetheless, we observe a gradual enhancement of the negative polarization branch in the ascending order of F-B-T-Ch types, along with an increase in reflectance curvature around 500 nm.

Our observations suggest at least for large C-complex asteroids a common mechanism underlies the diversity in optical properties. The observed trends would be explained by the surface composition of the asteroids, particularly optical heterogeneity caused by carbon’s varying levels of optical influence, primarily regulated by aqueous alteration of the surfaces.

Yuna G. Kwon, Stefano Bagnulo, Alberto Cellino

Comments: Accepted for publication in Astronomy & Astrophysics
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2307.15441 [astro-ph.EP] (or arXiv:2307.15441v1 [astro-ph.EP] for this version)
Submission history
From: Yuna G. Kwon
[v1] Fri, 28 Jul 2023 09:43:42 UTC (22,010 KB)
https://arxiv.org/abs/2307.15441
Astrobiology, Astrochemistry

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻