Orbitally derived thermal inertia (TI) values of surfaces allow for remote interpretation of rock and sediment physical characteristics. The evolving local times of the Mars Odyssey Thermal Emission Imaging System (THEMIS) mission have enabled surface temperature data collection over multiple seasons and local times over ∼9 Mars years (MY). We utilize this higher temporal resolution data set to separate TI values of individual materials within THEMIS pixels (100 m sampling). In this study, we focus on geologic units within Gusev, Gale, and Jezero crater landing sites to determine their respective TI and ground-truth our methods. We use the KRC model to predict temperatures for a range of homogeneous and two-component thermophysical mixing scenarios (laterally and vertically heterogeneous), and compare those to THEMIS brightness temperatures. The Gusev and Gale crater results are consistent with rover-based evaluations, indurated or clast-covered sands. The best-fit scenarios along the Jezero crater volcanic floor unit show low to moderate TI values representative of coarse sediment, volcaniclastic, or pyroclastic rocks. The light toned unit and western fan deposits both indicate sands and a moderate TI component; we interpret this as heavy fracturing within the rock. Difficulties in modeling some THEMIS temperatures are attributed to daily weather effects, local atmospheric dust variability, and real surface changes over time (e.g., dust deposition and removal); we also observe that some temperature observations lead to non-unique modeled physical solutions. Nevertheless, these methods can still rule out a significant range of material properties and provide meaningful geologic information about Mars' surface.Plain Language Summary Characterizing rock and sediment properties on Mars provides information about its past environmental and surface processes. Thermal inertia (TI) describes how easily materials can be warmed or cooled and can be determined using surface temperatures measured from orbit. TI values are proxies for sediment grain size and rock physical characteristics, which provide clues about Mars' geologic history. The THEMIS instrument, a multispectral thermal infrared camera aboard the Mars Odyssey orbiter, has measured temperatures for 9 Mars years (MY). We have selected three rover landing sites to study with these data. We compare THEMIS temperatures with modeled rock and sediment mixing scenarios. Gusev and Gale crater results agree with rover observations, mixtures of sediment with coarser sediment or lightly cemented rock. A volcanic unit in Jezero crater appears to have formed from volcanic sediments or bubbly lavas. The light toned unit in Jezero is consistent with a brokenup rocky surface covered with sand, and the western fan is dominated by sand-sized sediment. Clouds, dust, and frosts complicate models of THEMIS temperatures. Sometimes, the same temperatures arise from multiple rock/sediment mixing scenarios; this complicates interpretation. However, the methods in this study narrow down ...
Io is the most volcanically active and tidally influenced body in the solar system. Its paterae and mountains are among its most distinguishing features. Paterae, similar to calderas, are volcanotectonic collapse features, often with active lava flows on their floors. Io's mountains are some of the highest in the solar system and contain many linear features that reveal global and regional stresses. This study investigates the relationship of linear features associated with paterae and mountains to stress fields associated with proposed mechanisms of formation: tidal forces, crustal loading, and local tectonics.
Io is a priority destination for solar system exploration, as it is the best natural laboratory to study the intertwined processes of tidal heating, extreme volcanism, and atmospheremagnetosphere interactions. Io exploration is relevant to understanding terrestrial planets and moons (including the early Earth), ocean worlds, and exoplanets across the cosmos.1. Io is a priority destination for future exploration. Jupiter's innermost large moon, Io, is the most geologically active world in the solar system (Fig. 1). Io's surface is marked by hundreds of active volcanoes, erupting lava fountains, evolving sulfurous ices, enormous mountains, and deposits from towering volcanic plumes that pollute the Jovian system and feed its enormous magnetosphere. This unparalleled activity is powered by rampant tidal heating, where the gravitational interactions between Io and its neighboring moons result in time-varying tides from Jupiter that deform and heat Io's interior. Io is the best natural laboratory to study these intertwined processes, and it is a vitally important destination for addressing high priority, cross-cutting science investigations relevant to broad swaths of planetary science-from the Hadean Earth-Moon system when life emerged, to present-day potentially habitable ocean worlds, and distant exoplanets where conditions are even more extreme. Characterization of Io will guide future observations of both ocean worlds and exoplanetary targets. In a sense, Io is the uninhabitable world that teaches us how habitable worlds form and work.
Io is a priority destination for solar system exploration, as it is the best natural laboratory to study the intertwined processes of tidal heating, extreme volcanism, and atmospheremagnetosphere interactions. Io exploration is relevant to understanding terrestrial planets and moons (including the early Earth), ocean worlds, and exoplanets across the cosmos. The scope and importance of science questions at Io necessitates a broad portfolio of research and analysis, telescopic observations, and planetary missions-including a dedicated New Frontiers class Io mission.Recommendation 1: We strongly recommend a dedicated New Frontiers class Io mission for the next decade. As outlined in a companion white paper, The Science Case for Io, Io is a priority destination for future exploration. There is much that can only be learned through detailed in situ measurements and observations from a dedicated Io mission. Even as nextgeneration telescopes come online, we are unlikely to achieve spatial resolutions better than tens of kilometers, and we cannot make observations of Io's poles or night hemisphere. There are also entire suites of in situ measurements which are simply not possible without visiting Io-like measuring Io's gravity and magnetic fields, or sampling its plumes and atmosphere. Furthermore, a dedicated mission to Io in the coming decade is timely, as it would enhance the science return from current and future Jupiter-system missions (Juno, Europa Clipper, JUICE), enabling true system science and contemporaneous investigations of the tidal and orbital evolution of the entire Jovian system. A mission to Io could also inform and guide forthcoming exoplanet observations with next-generation telescopes, and inform our understanding of the origins of life through implications for the early Earth and tidally heated ocean worlds like Europa, Enceladus, and Titan.Box 1 outlines a notional mission concept for a dedicated Io mission that could plausibly address all of the Priority Science Questions outlined in The Science Case for Io. This "Io Observer" concept is an amalgam of multiple different concepts, ideas, and mission proposals [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] . While we highlight one particular concept we encourage the decadal survey to allow flexibility in implementation. The past decade is characterized by mission selections that exemplify how new, innovative, and bold ideas have the power to transform the field (e.g., Dragonfly 17 ). A Jupiterorbiting, multiple-flyby, Io Observer may be the prevailing approach at this time, but out-of-thebox concepts may be capable of addressing a preponderance of Priority Science Questions, including orbiters, landers, impactors, and distant observers.The cost of the notional Io Observer mission concept outlined in Box 1 requires a detailed study by the decadal survey (see Recommendation 2). Io mission concepts have previously targeted either the Discovery program 1,3,7,10,12,15 or the New Frontiers program 2,6,8-9,13-14 , with sporadic discussion of Fla...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.