Jupiter Trojans Archives

Left: Spatial distribution of the ROIs within the Red, Transitional, and Blue units used to extract the data.

Infrared-to-visible Albedo Ratio Of Phobos: Comparison With Primitive Asteroids

by Keith CowingAugust 17, 2026August 17, 2026

[astro-ph.EP] Aims. The ratio between infrared and visible albedo, pIR/pV, provides a simple proxy for the spectral slope of asteroid surfaces between the visible and near-infrared wavelength ranges. The aim […]

Modeled mixtures of magnesium rich pyroxenes and olivines plotted alongside the spectrum of 267 Tirza and 1268 Libya. The addition of pyroxene to the olivine mixtures changes the behavior of the spectrum at long wavelengths, broadening this emission feature from the distinct emission peak(s) seen in the spectra of olivine and pyroxene alone. Spectral features of olivine are marked in light green and of pyroxenes are marked in dark purple to highlight commonalities with the asteroid spectra. The feature at 19.5 µm is common to both olivine and pyroxene. The spectrum of 267 Tirza in particular shows evidence of both olivine and pyroxene. All mixtures shown here contain both amorphous and crystalline silicates mixed in a 3:1 ratio, while the proportion of olivine and pyroxene is varied. The shaded grey box highlights the location of a known artefact in the SL Spitzer data (the SL teardrop). Spectra of crystalline silicates are sourced from Koike et al. (2003) and Chihara et al. (2002), spectra of amorphous silicates are derived from optical constants from J¨ager et al. (1994); Dorschner et al. (1995) and J¨ager et al. (2003) (see text for modeling details and silicate compositions). -- astro-ph.EP

Astrochemistry, Astrogeology, Comets and Asteroids, Imaging & Spectroscopy, Meteorites & Asteroids, Status Report

Comparative Mid-Infrared Spectroscopy of Dark, Primitive Asteroids: Does Shared Taxonomic Class Indicate Shared Silicate Composition?

by Keith CowingMay 1, 2024May 1, 2024

Primitive asteroids with low albedos and red slopes in the visible and near infrared (VNIR) are found in both the Main Belt and the Jupiter Trojan clouds.