Catalogue of ISO LWS observations of asteroids

TL;DR

This paper refines and calibrates ISO LWS observations of four large main-belt asteroids, providing high-quality spectral data and derived physical properties to support future mineralogical and physical studies.

Contribution

It presents an improved data reduction and calibration process for ISO LWS asteroid observations, enhancing data quality for scientific analysis.

Findings

Photometric accuracy better than 10%

Derived diameters and albedos from thermophysical modeling

Compared Vesta's thermal lightcurve with model predictions

Abstract

(Abridged) The Long Wavelength Spectrometer (LWS) onboard the Infrared Space Observatory (ISO) observed the four large main-belt asteroids (1) Ceres, (2) Pallas, (4) Vesta, and (10) Hygiea multiple times. The photometric and spectroscopic data cover the wavelength range between 43 and 197 um, and are a unique dataset for future investigations and detailed characterisations of these bodies. The standard ISO archive products, produced through the last post-mission LWS pipeline, were still affected by instrument artefacts. Our goal was to provide the best possible data products to exploit the full scientific potential of these observations. We performed a refined reduction of all measurements, corrected for various instrumental effects, and re-calibrated the data. We outline the data reduction process and give an overview of the available data and the quality of the observations. We apply a thermophysical model to the flux measurements to derive far-IR based diameter and albedo values of the asteroids. The measured thermal rotational lightcurve of (4) Vesta is compared to model predictions. The absolute photometric accuracy of the data products was foubd to be better than 10%. The calibrated spectra will serve as source for future mineralogical studies of dwarf planets and dwarf planet candidates.