Review of Spitzer Space Telescope observations of small bodies

Abstract

Abstract. The Spitzer Space Telescope (SST), aloft for over two years at time of writing, has so far devoted almost 600 hours of observing time to Solar System science, and small bodies make up a significant fraction of the objects that have been observed. For the first time we now have high accuracy mid-infrared data to study the fundamental mineralogical and physical properties of a large number of objects of different types. In this paper we review some of the exciting recent results derived from SST photometry (in six bands from 3.6 to 70 µm) and spectroscopy (from 5 to 40 µm) of asteroids and comets. The observations reveal their spectral energy distributions (SEDs), and we discuss three important science goals that can be addressed with these data: (1) finding compositional diagnostics of these objects, (2) determining their bulk thermal properties, and (3) understanding the surface evolution of primitive and icy bodies. We focus primarily on comet-asteroid transition objects, low-albedo asteroids, cometary nuclei, Trojans, Centaurs, and trans-Neptunian objects. In particular, we will show: emissivity features in the SEDs and identification of the compositional sources, the constraints on thermal inertia and infrared beaming through the samples of the thermal continuum, and an intercomparison of albedos across dynamically-related bodies.

MIR Spectra and Analysis of Jovian Trojan Asteroids

“…Trojan surfaces have low albedos and red-sloped spectra in the visible and near-infrared (VNIR; 0.8-4.0 μm) with no diagnostic absorption features (Jewitt & Luu 1990;Cruikshank et al 2001;Emery & Brown 2003;Fernández et al 2003;Emery et al 2011;Yang & Jewitt 2011;Romanishin & Tegler 2018). Trojans fall into two distinct groups based on spectral slope: red-sloped and less red-sloped (Emery et al 2011).…”