Linear Polarization Variations and Circular Polarization are Common Among Airless Bodies

Fuente: arXiv
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Autores principales: Wiktorowicz, Sloane J., Bayless, Amanda J., Nofi, Larissa A.
Formato: Preprint
Publicado: 2026
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author Wiktorowicz, Sloane J.
Bayless, Amanda J.
Nofi, Larissa A.
author_facet Wiktorowicz, Sloane J.
Bayless, Amanda J.
Nofi, Larissa A.
contents Using the POLISH2 polarimeter at the Lick Observatory Shane 3-m and Nickel 1-m telescopes, we discover rotation phase-locked variations in linear polarization to be common among asteroids and a NEO in a clear, 383 to 720 nm bandpass. Essentially all bodies in our eight-year study harbor statistically significant, repeatable linear polarization variations at the $0.01\% = 100$ ppm level or above (1 Ceres, 2 Pallas, 3 Juno, 4 Vesta, 6 Hebe, 7 Iris, 12 Victoria, 15 Eunomia, 16 Psyche, 132 Aethra, 216 Kleopatra, and 65803 Didymos). Since polarimetry is a differential technique, such variations cannot be due to shape changes and must be caused by heterogeneity in surface albedo and/or composition. While (4) Vesta has long been known to exhibit large, repeatable polarization variations across its surface, we discover the variations on (6) Hebe, (12) Victoria, and (65803) Didymos to be 1.5 to 3.5 times as large. We hypothesize that the \textit{DART} impact with Dimorphos blanketed Didymos with depolarizing ejecta, which suggests pristine variations across Didymos to have been even larger. As the only NEO in this study with data quality sufficient to investigate polarization variations, Didymos' huge variations suggest they may be common among NEOs. We also discover optical circular polarization to be enhanced for low-albedo, M type asteroids, which is correlated with their large radar albedos. Thus, we present optical circular polarimetry as an alternative method for the identification of metalliferous bodies.
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id arxiv_https___arxiv_org_abs_2602_24196
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Linear Polarization Variations and Circular Polarization are Common Among Airless Bodies
Wiktorowicz, Sloane J.
Bayless, Amanda J.
Nofi, Larissa A.
Earth and Planetary Astrophysics
Instrumentation and Methods for Astrophysics
Using the POLISH2 polarimeter at the Lick Observatory Shane 3-m and Nickel 1-m telescopes, we discover rotation phase-locked variations in linear polarization to be common among asteroids and a NEO in a clear, 383 to 720 nm bandpass. Essentially all bodies in our eight-year study harbor statistically significant, repeatable linear polarization variations at the $0.01\% = 100$ ppm level or above (1 Ceres, 2 Pallas, 3 Juno, 4 Vesta, 6 Hebe, 7 Iris, 12 Victoria, 15 Eunomia, 16 Psyche, 132 Aethra, 216 Kleopatra, and 65803 Didymos). Since polarimetry is a differential technique, such variations cannot be due to shape changes and must be caused by heterogeneity in surface albedo and/or composition. While (4) Vesta has long been known to exhibit large, repeatable polarization variations across its surface, we discover the variations on (6) Hebe, (12) Victoria, and (65803) Didymos to be 1.5 to 3.5 times as large. We hypothesize that the \textit{DART} impact with Dimorphos blanketed Didymos with depolarizing ejecta, which suggests pristine variations across Didymos to have been even larger. As the only NEO in this study with data quality sufficient to investigate polarization variations, Didymos' huge variations suggest they may be common among NEOs. We also discover optical circular polarization to be enhanced for low-albedo, M type asteroids, which is correlated with their large radar albedos. Thus, we present optical circular polarimetry as an alternative method for the identification of metalliferous bodies.
title Linear Polarization Variations and Circular Polarization are Common Among Airless Bodies
topic Earth and Planetary Astrophysics
Instrumentation and Methods for Astrophysics
url https://arxiv.org/abs/2602.24196