Tohoku-Hiroshima-Nagoya planetary spectra library: a method for characterizing planets in the visible to near infrared

Abstract

Context. A comprehensive framework for comparing spectral data from different planets has yet to be established. This framework is needed for the study of extrasolar planets and objects within the solar system. Aims. We completed observations to compile a library of planet spectra for all planets, some moons, and some dwarf planets in the solar system to study their general spectroscopic and photometric natures. Methods. During May and November of 2008, we acquired spectra for the planets using TRISPEC, which is capable of simultaneous three-band spectroscopy across a wide wavelength range of 0.45−2.5 μm with low resolving power (λ/Δλ ∼ 140−360). Results. Patterns emerge when comparing the spectra. By analyzing their general spectroscopic and photometric natures, we show that it is possible to distinguish between gas planets, soil planets, and ice planets. These methods can be applied to extrasolar observations acquired using low resolution spectrography or broad-band filters.Conclusions. The present planet spectral library is the first library to contain observational spectra for all of the solar system planets, based on simultaneous observations at visible and near infrared wavelengths. This library will be a useful reference for analyzing extrasolar planet spectra and calibrating planetary data sets.

A Catalog of Spectra, Albedos, and Colors of Solar System Bodies for Exoplanet Comparison

“…The THN-PSL paper discusses several initial observations of moons that were contaminated with light from their host planet rendering their spectra inaccurate (080505 Callisto, 081125 Dione, 080506 Io, and 080506 Rhea). These objects (with the exception of Callisto) were observed again and the extra light was removed in a different fashion to more accurately correct the spectra (Lundock et al, 2009). Callisto was not re-observed and therefore the THN-PSL Calisto data remained contaminated (Fig.3).…”

“…Geometric albedos for 19 Solar System bodies for Ceres, Dione, Earth, Jupiter, Moon, Neptune, Rhea, Saturn, Titan, Uranus (albedos calculated in this paper based on un-calibrated data by Lundock et al, 2009), Callisto , Enceladus (Filacchione et al, 2012), Europa , Ganymede , Io , Mars (McCord & Westphal, 1971), Mercury (Mallama, 2017), Pluto Protopapa et al, 2008), and Venus (Meadows 2006 (theoretical); Pollack et al 1978 (observation) , b , c , d , e (Meadows, 2006), f , g (Karkoschka, 1998), h (Lane & Irvine, 1973), i (McCord & Westphal, 1971), j (Mallama, 2017), k (Fink & Larson, 1979), l Protopapa et al, 2008), m , n (Cassini VIMS -NASA PDS). Items are arranged by body type then by distance from the Sun.…”

“…We use un-calibrated and calibrated spectra as well as albedos when available from the literature to compile our reference catalog. About half of the spectra and albedos we derive in this paper are based on un-calibrated observations obtained from the Tohoku-Hiroshima-Nagoya Planetary Spectral Library (THN-PSL) (Lundock et al, 2009), which provides a large coherent dataset of uncalibrated data taken with the same telescope. Our analysis shows contamination of part of that dataset, as discussed in section 2.1 and 2.2, therefore we only include a subset of their data in our catalog (see discussion 4.3).…”

Geology and Photometric Variation of Solar System Bodies with Minor Atmospheres: Implications for Solid Exoplanets

“…Therefore, it is important to examine the detectability of their surface signatures from a distance. In the context of future applications to exoplanets, spectra of Solar System bodies have been compiled, and characterization based on color-color plots has been discussed (Traub, 2003;Lundock et al, 2009;Crow et al, 2011). Mallama (2009) proposed the characterization of terrestrial exoplanets through orbital phase curves based on the empirical phase curves of Solar System planets.…”

Analyzing Atmospheric Temperature Profiles and Spectra of M Dwarf Rocky Planets

“…Our chosen value of 0.1 for the surface albedo is based on solar system findings that rocky bodies without an extended atmosphere and icy surface are dark. For instance, the Bond albedos of Mercury, the Moon and Ceres are all within 0−0.2 (Lundock et al 2009;Madden & Kaltenegger 2018). Also, potential surface materials for exoplanets are thought to possess low albedos (Hu et al 2012;Mansfield et al submitted).…”