The Ices on Transneptunian Objects and Centaurs

Bérgh, C. de; Schaller, E. L.; Brown, Michael E.; Brunetto, R.; Cruikshank, D. P.; Schmitt, Bernard

doi:10.1007/978-1-4614-3076-6_4

Cited by 15 publications

(11 citation statements)

References 150 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The average thermal inertia of classical TNOs or Plutinos about 47 AU appears very low about 2 ± 0.5 J/m 2 /K/s 1/2 . Water ice has been detected in its crystalline form on the surface of all the individual objects listed in Table 2 (De Bergh et al 2013). On Haumea in particular, a mixture of amorphous and crystalline ice better fits the data (Pinilla-alonso et al 2009).…”

Section: Thermal Inertia Vs Heliocentric Distancementioning

confidence: 99%

Low thermal inertias of icy planetary surfaces

Ferrari

Lucas

2016

A&A

View full text Add to dashboard Cite

Context. Thermal inertias of atmosphereless icy planetary bodies happen to be very low. Aims. We relate the thermal inertia to the regolith properties such as porosity, grain size, ice form and heat transfer processes to understand why it is low. We interpret the dichotomy in thermal inertia of the surface of Mimas in terms of changes in regolith properties. We predict how the thermal inertia of these bodies may vary with heliocentric distance depending on these properties. Methods. We combine available models of conductivity by contact or radiation to understand what heat transfer process is predominant.Results. The magnitude of the thermal inertia of a porous icy regolith is mainly governed by the crystalline or amorphous ice forms, and the quality of contacts between grains. Beyond the orbit of Jupiter, thermal inertias as low as a few tens J/m 2 /K/s 1/2 are difficult to reproduce with plausible porosity and grains sizes made of crystalline ice unless contacts are loose. This is, on the contrary, straightforward for regoliths of sub-cm-sized grains made of amorphous water ice. This study points out the importance of including the temperature dependence of thermophysical properties of water ice forms and the radiative conduction in thermal models of these bodies. The relatively high thermal inertia of the leading face of Mimas can be explained by a regolith of crystalline ice grains in tight contacts, which are eventually sintered by the bombardment of high energy electrons. The low thermal inertia of its trailing face is easily reproduced by a regolith of moderate porosity with sub-mm-sized grains of amorphous ice. The characteristic decrease of thermal inertia with heliocentric distance of icy atmosphereless surfaces and the very low thermal inertia of relevant trans-Neptunian objects are easily explained if amorphous ice is present at cm depths below a thin layer of crystalline ice.

show abstract

Section: Thermal Inertia Vs Heliocentric Distancementioning

confidence: 99%

Low thermal inertias of icy planetary surfaces

Ferrari

Lucas

2016

A&A

View full text Add to dashboard Cite

show abstract

“…All of these quantities vary with surface composition and temperature, but we here consider H 2 O-ice surfaces, which are by far the most common in the Kuiper belt (e.g. de Bergh et al 2013), and assume a constant ρ = 1000 kg m −3 . The temperature dependence of c and κ has been studied by a number of authors, and a recent compilation has been presented by Castillo-Rogez et al (2012).…”

Section: Thermal Inertia and Dependence With Heliocentric Distancementioning

confidence: 99%

“TNOs are Cool”: A survey of the trans-Neptunian region

Lellouch

Santos-Sanz

Lacerda

et al. 2013

A&A

137

143

View full text Add to dashboard Cite

Aims. The goal of this work is to characterize the ensemble thermal properties of the Centaurs / trans-Neptunian population. Methods. Thermal flux measurements obtained with Herschel/PACS and Spitzer/MIPS provide size, albedo, and beaming factors for 85 objects (13 of which are presented here for the first time) by means of standard radiometric techniques. The measured beaming factors are influenced by the combination of surface roughness and thermal inertia effects. They are interpreted within a thermophysical model to constrain, in a statistical sense, the thermal inertia in the population and to study its dependence on several parameters. We use in particular a Monte-Carlo modeling approach to the data whereby synthetic datasets of beaming factors are created using random distributions of spin orientation and surface roughness. Results. Beaming factors η range from values <1 to ∼2.5, but high η values (>2) are lacking at low heliocentric distances (r h < 30 AU). Beaming factors lower than 1 occur frequently (39% of the objects), indicating that surface roughness effects are important. We determine a mean thermal inertia for Centaurs/ TNO of Γ = (2.5 ± 0.5) J m −2 s −1/2 K −1 , with evidence of a trend toward decreasing Γ with increasing heliocentric (by a factor ∼2.5 from 8-25 AU to 41-53 AU). These thermal inertias are 2-3 orders of magnitude lower than expected for compact ices, and generally lower than on Saturn's satellites or in the Pluto/Charon system. Most high-albedo objects are found to have unusually low thermal inertias. Our results suggest highly porous surfaces, in which the heat transfer is affected by radiative conductivity within pores and increases with depth in the subsurface.

show abstract

“…Reflectance spectroscopy has had a remarkable record of revealing the surface compositions of icy solar system bodies, ranging from satellites of the four giant planets to icy dwarf planets beyond Neptune's orbit (see reviews by Cruikshank et al 1998a,b;Clark et al 2013;and de Bergh et al 2013;and references therein). In addition to nearly ubiquitous water ice, more exotic ices of methane, ethane, nitrogen, oxygen, hydrogen cyanide, ammonia, carbon monoxide, carbon dioxide, and sulfur dioxide have been identified on outer solar system bodies from their characteristic patterns of absorption bands imprinted on visible to infrared reflectance spectra.…”

Section: Introductionmentioning

confidence: 99%

Near-infrared spectral monitoring of Pluto’s ices: Spatial distribution and secular evolution

Grundy

Olkin

Young

et al. 2013

Icarus

View full text Add to dashboard Cite

a b s t r a c tWe report results from monitoring Pluto's 0.8 to 2.4 lm reflectance spectrum with IRTF/SpeX on 65 nights over the dozen years from 2001 to 2012. The spectra show vibrational absorption features of simple molecules CH 4 , CO, and N 2 condensed as ices on Pluto's surface. These absorptions are modulated by the planet's 6.39 day rotation period, enabling us to constrain the longitudinal distributions of the three ices. Absorptions of CO and N 2 are concentrated on Pluto's anti-Charon hemisphere, unlike absorptions of less volatile CH 4 ice that are offset by roughly 90°from the longitude of maximum CO and N 2 absorption. In addition to the diurnal variations, the spectra show longer term trends. On decadal timescales, Pluto's stronger CH 4 absorption bands have been getting deeper, while the amplitude of their diurnal variation is diminishing, consistent with additional CH 4 absorption at high northern latitudes rotating into view as the sub-Earth latitude moves north (as defined by the system's angular momentum vector). Unlike the CH 4 absorptions, Pluto's CO and N 2 absorptions appear to be declining over time, suggesting more equatorial or southerly distributions of those species. Comparisons of geometrically-matched pairs of observations favor geometric explanations for the observed secular changes in CO and N 2 absorption, although seasonal volatile transport could be at least partly responsible. The case for a volatile transport contribution to the secular evolution looks strongest for CH 4 ice, despite it being the least volatile of the three ices.

show abstract

The Ices on Transneptunian Objects and Centaurs

Cited by 15 publications

References 150 publications

Low thermal inertias of icy planetary surfaces

Low thermal inertias of icy planetary surfaces

“TNOs are Cool”: A survey of the trans-Neptunian region

Near-infrared spectral monitoring of Pluto’s ices: Spatial distribution and secular evolution

Contact Info

Product

Resources

About