JWST Reveals Varied Origins Between Jupiter's Irregular Satellites

Fuente: arXiv
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Auteurs principaux: Sharkey, Benjamin N. L., Rivkin, Andrew S., Cartwright, Richard J., Holler, Bryan J., Emery, Joshua P., Thomas, Cristina
Format: Preprint
Publié: 2025
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author Sharkey, Benjamin N. L.
Rivkin, Andrew S.
Cartwright, Richard J.
Holler, Bryan J.
Emery, Joshua P.
Thomas, Cristina
author_facet Sharkey, Benjamin N. L.
Rivkin, Andrew S.
Cartwright, Richard J.
Holler, Bryan J.
Emery, Joshua P.
Thomas, Cristina
contents We report observations of eight Jovian irregular satellites with JWST's NIRSpec instrument: Himalia, Elara, Pasiphae, Sinope, Lysithea, Carme, Ananke, and Themisto. Irregular satellite families, which are presumed to have formed via collisions, contain various Trojan-like and C-type-asteroid-like surfaces. We sample the three largest members of the Himalia satellite family, detecting the presence of complexed CO$_2$ and a unique absorption band from $\sim2.7-3.6\ μm$ whose character correlates with satellite size. The two largest irregular satellites, Himalia family members Himalia and Elara, contain ammoniated phyllosilicates that are not seen in the meteorite inventory. We propose that the Himalia parent body was heterogeneous and formed with materials similar to Ceres-like ammonium-bearing asteroids. Several small ($D\sim 10km$) irregular satellites closely track the colors and absorption bands of ``red'' Jovian Trojans, demonstrating that these compositions are retained amongst the products of collisions that occurred after Jovian capture. We report the first detection of aqueous alteration products in the retrograde satellite swarm, finding Ananke's 3 micron band to closely match phyllosilicates seen in C2 chondrites. Notably, objects with OH absorption features similar to the Trojan asteroid Eurybates are found in both the retrograde Pasiphae family and the prograde Himalia family, confounding a simple link between such materials and a single surface type. The irregular satellites appear consistent with some materials that experienced alteration from liquid water and others that did not. Consequently, Jupiter may have captured bodies that formed from different initial compositions, or bodies that experienced different levels of heating, driving differential alteration processes.
format Preprint
id arxiv_https___arxiv_org_abs_2501_16484
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle JWST Reveals Varied Origins Between Jupiter's Irregular Satellites
Sharkey, Benjamin N. L.
Rivkin, Andrew S.
Cartwright, Richard J.
Holler, Bryan J.
Emery, Joshua P.
Thomas, Cristina
Earth and Planetary Astrophysics
We report observations of eight Jovian irregular satellites with JWST's NIRSpec instrument: Himalia, Elara, Pasiphae, Sinope, Lysithea, Carme, Ananke, and Themisto. Irregular satellite families, which are presumed to have formed via collisions, contain various Trojan-like and C-type-asteroid-like surfaces. We sample the three largest members of the Himalia satellite family, detecting the presence of complexed CO$_2$ and a unique absorption band from $\sim2.7-3.6\ μm$ whose character correlates with satellite size. The two largest irregular satellites, Himalia family members Himalia and Elara, contain ammoniated phyllosilicates that are not seen in the meteorite inventory. We propose that the Himalia parent body was heterogeneous and formed with materials similar to Ceres-like ammonium-bearing asteroids. Several small ($D\sim 10km$) irregular satellites closely track the colors and absorption bands of ``red'' Jovian Trojans, demonstrating that these compositions are retained amongst the products of collisions that occurred after Jovian capture. We report the first detection of aqueous alteration products in the retrograde satellite swarm, finding Ananke's 3 micron band to closely match phyllosilicates seen in C2 chondrites. Notably, objects with OH absorption features similar to the Trojan asteroid Eurybates are found in both the retrograde Pasiphae family and the prograde Himalia family, confounding a simple link between such materials and a single surface type. The irregular satellites appear consistent with some materials that experienced alteration from liquid water and others that did not. Consequently, Jupiter may have captured bodies that formed from different initial compositions, or bodies that experienced different levels of heating, driving differential alteration processes.
title JWST Reveals Varied Origins Between Jupiter's Irregular Satellites
topic Earth and Planetary Astrophysics
url https://arxiv.org/abs/2501.16484