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Nature 451, 437-440 (2008) In Fig. 3a, the descriptions of the continuous and dotted curves were inadvertently swapped. The continuous line corresponds to the modified synthetic thermal profile (storms reaching [...]

Most of the objects in the trans-Neptunian belt (TNb) and related populations move in prograde orbits with low eccentricity and inclination. However, the list of icy minor bodies moving in orbits with an inclination above 408 has increased in recent years. The origin of these bodies, and in particular of those objects in retrograde orbits, is not well determined, and different scenarios are considered, depending on their inclination and perihelion. In this paper, we present new observational and dynamical data of two objects in retrograde orbits, 2008 YB3 and 2005 VD.We find that the surface of these extreme objects is depleted of ices and does not contain the "ultra-red" matter typical of some Centaurs. Despite small differences, these objects share common colors and spectral characteristics with the Trojans, comet nuclei, and the group of grey Centaurs. All of these populations are supposed to be covered by a mantle of dust responsible for their reddish-to-neutral color. To investigate if the surface properties and dynamical evolution of these bodies are related, we integrate their orbits for 108 years to the past. We find a remarkable difference in their dynamical evolutions: 2005 VD's evolution is dominated by a Kozai resonance with planet Jupiter while that of 2008 YB3 is dominated by close encounters with planets Jupiter and Saturn. Our models suggest that the immediate site of provenance of 2005 VD is the in the Oort Cloud, whereas for 2008 YB3 it is in the trans-Neptunian region. Additionally, the study of their residence time shows that 2005 VD has spent a larger lapse of time moving in orbits in the region of the giant planets than 2008 YB3. Together with the small differences in color between these two objects, with 2005 VD being more neutral than 2008 YB3, this fact suggests that the surface of 2005 VD has suffered a higher degree of processing, which is probably related to cometary activity episodes. [ABSTRACT FROM AUTHOR]

Context. Primitive asteroids contain complex organic material and ices relevant to the origin of life on Earth. These types of asteroids are the target of several sample-return missions to be launched in the next years. 1999 JU3 is the target of the Japanese Aerospace Exploration Agency's Hayabusa 2 mission. Aims. 1999 JU3 has been previously identified as a C-class asteroid. Spectroscopic observations at longer wavelengths will help to constrain its composition. Methods. We obtained spectroscopy of 1999 JU3 from 0.85 to 2.2 μm, with the 3.6 m Telescopio Nazionale Galileo using the low-resolution mode of the Near Infrared Camera Spectrograph. Results. We present a near-infrared spectrum of 1999 JU3 from 0.85 to 2.2 μ that is consistent with previously published spectra and with its C-type classification. Conclusions. Our spectrum confirms the primitive nature of 1999 JU3 and its interest as target of the sample-return mission Hayabusa 2. [ABSTRACT FROM AUTHOR]

The dwarf planets Sedna, Gonggong, and Quaoar are interesting in being somewhat smaller than the methane-rich bodies of the Kuiper Belt (Pluto, Eris, Makemake), yet large enough to be spherical and to have possibly undergone interior melting and differentiation. They also reside on very different orbits, making them an ideal suite of bodies for untangling effects of size and orbit on present day surface composition. We observed Sedna, Gonggong, and Quaoar with the NIRSpec instrument on the James Webb Space Telescope (JWST). All three bodies were observed in the low-resolution prism mode at wavelengths spanning 0.7 to 5.2 μm. Quaoar was additionally observed at 10× higher spectral resolution from 0.97 to 3.16 μm using medium-resolution gratings. Sedna's spectrum shows a large number of absorption features due to ethane (C 2 H 6), as well as acetylene (C 2 H 2), ethylene (C 2 H 4), H 2 O, and possibly CO 2. Gonggong's spectrum also shows several, but fewer and weaker, ethane features, along with stronger and cleaner H 2 O features and CO 2 complexed with other molecules. Quaoar's prism spectrum shows even fewer and weaker ethane features, the deepest and cleanest H 2 O features, a feature at 3.2 μm possibly due to HCN, and CO 2 ice. The higher-resolution medium grating spectrum of Quaoar reveals several overtone and combination bands of ethane and methane (CH 4). Spectra of all three objects show steep red spectral slopes and strong, broad absorptions between 2.7 and 3.6 μm indicative of complex organic molecules. The suite of light hydrocarbons and complex organic molecules are interpreted as the products of irradiation of methane. We infer that the differences in apparent abundances of irradiation products among these three similarly-sized bodies are likely due to their distinctive orbits, which lead to different timescales of methane retention and to different charged particle irradiation environments. In all cases, however, the continued presence of light hydrocarbons implies a resupply of methane to the surface. We suggest that these three bodies have undergone internal melting and geochemical evolution similar to the larger dwarf planets and distinct from all smaller KBOs. The feature identification presented in this paper is the first step of analysis, and additional insight into the relative abundances and mixing states of materials on these surfaces will come from future spectral modeling of these data. • New JWST NIRSpec infrared spectral observations of Sedna, Gonggong, and Quaoar. • Absorptions due to C 2 H 6 , C 2 H 2 , and C 2 H 4 indicate active irradiation chemistry. • Differences among the three bodies are likely due to different orbits. • The spectra are distinct from those of smaller KBOs. • These bodies may have undergone internal melting and geochemical evolution. [ABSTRACT FROM AUTHOR]

James Webb Space Telescope's NIRSpec infrared imaging spectrometer observed the outer solar system dwarf planets Eris and Makemake in reflected sunlight at wavelengths spanning 1 through 5 μm. Both objects have high albedo surfaces that are rich in methane ice, with a texture that permits long optical path lengths through the ice for solar photons. There is evidence for N 2 ice absorption around 4.2 μm on Eris, though not on Makemake. No CO ice absorption is seen at 4.67 μm on either body. For the first time, absorption bands of two heavy isotopologues of methane are observed at 2.615 μm (13CH 4), 4.33 μm (12CH 3 D), and 4.57 μm (12CH 3 D). These bands enable us to measure D/H ratios of (2.5 ± 0.5) × 10−4 and (2.9 ± 0.6) × 10−4, along with 13C/12C ratios of 0.012 ± 0.002 and 0.010 ± 0.003 in the surface methane ices of Eris and Makemake, respectively. The measured D/H ratios are much lower than that of presumably primordial methane in comet 67P/Churyumov-Gerasimenko, but they are similar to D/H ratios in water in many comets and larger outer solar system objects. This similarity suggests that the hydrogen atoms in methane on Eris and Makemake originated from water, indicative of geochemical processes in past or even ongoing hot environments in their deep interiors. The 13C/12C ratios are consistent with commonly observed solar system values, suggesting no substantial enrichment in 13C as could happen if the methane currently on their surfaces was the residue of a much larger inventory that had mostly been lost to space. Possible explanations include geologically recent outgassing from the interiors as well as processes that cycle the surface methane inventory to keep the uppermost surfaces refreshed. • New JWST NIRSpec infrared spectral observations of Eris and Makemake. • Absorption bands of 13CH4 and CH3D used to measure isotopic ratios in CH4. • Similarity to D/H in water suggests source in interior geochemistry. [ABSTRACT FROM AUTHOR]

Charon, Pluto's largest moon, has been extensively studied, with research focusing on its primitive composition and changes due to radiation and photolysis. However, spectral data have so far been limited to wavelengths below 2.5 μm, leaving key aspects unresolved. Here we present the detection of carbon dioxide (CO 2 ) and hydrogen peroxide (H 2 O 2 ) on the surface of Charon's northern hemisphere, using JWST data. These detections add to the known chemical inventory that includes crystalline water ice, ammonia-bearing species, and tholin-like darkening constituents previously revealed by ground- and space-based observations. The H 2 O 2 presence indicates active radiolytic/photolytic processing of the water ice-rich surface by solar ultraviolet and interplanetary medium Lyman-α photons, solar wind, and galactic cosmic rays. Through spectral modeling of the surface, we show that the CO 2 is present in pure crystalline form and, possibly, in intimately mixed states on the surface. Endogenically sourced subsurface CO 2 exposed on the surface is likely the primary source of this component, with possible contributions from irradiation of hydrocarbons mixed with water ice, interfacial radiolysis between carbon deposits and water ice, and the implantation of energetic carbon ions from the solar wind and solar energetic particles., (© 2024. The Author(s).)

Lithium, a critical natural resource integral to modern technology, has influenced diverse industries since its discovery in the 1950s. Of particular interest is lithium-7, the most prevalent lithium isotope on Earth, playing a vital role in applications such as batteries, metal alloys, medicine, and nuclear research. However, its extraction presents significant environmental and logistical challenges. This article explores the potential for lithium exploration on the Moon, driven by its value as a resource and the prospect of cost reduction due to the Moon's lower gravity, which holds promise for future space exploration endeavors. Additionally, the presence of lithium in the solar wind and its implications for material transport across celestial bodies are subjects of intrigue. Drawing from a limited dataset collected during the Apollo missions (Apollo 12, 15, 16, and 17) and leveraging artificial intelligence techniques and sample expansion through bootstrapping, this study develops predictive models for lithium-7 concentration based on spectral patterns. The study areas encompass the Aitken crater, Hadley Rima, and the Taurus-Littrow Valley, where higher lithium concentrations are observed in basaltic lunar regions. This research bridges lunar geology and the formation of the solar system, providing valuable insights into celestial resources and enhancing our understanding of space. The data used in this study were obtained from the imaging sensors (infrared, visible, and ultraviolet) of the Clementine satellite, which significantly contributed to the success of our research. Furthermore, the study addresses various aspects related to statistical analysis, sample quality validation, resampling, and bootstrapping. Supervised machine learning model training and validation, as well as data import and export, were explored. The analysis of data generated by the Clementine probe in the near-infrared (NIR) and ultraviolet-visible (UVVIS) spectra revealed evidence of the presence of lithium-7 (Li-7) on the lunar surface. The distribution of Li-7 on the lunar surface is non-uniform, with varying concentrations in different regions of the Moon identified, supporting the initial hypothesis associating surface Li-7 concentration with exposure to solar wind. While a direct numerical relationship between lunar topography and Li-7 concentration has not been established due to morphological diversity and methodological limitations, preliminary results suggest significant economic and technological potential in lunar lithium exploration and extraction.

It has been suggested that Earth's current supply of water was delivered by asteroids, some time after the collision that produced the Moon (which would have vaporized any of the pre-existing water). So far, no measurements of water ice on asteroids have been made, but its presence has been inferred from the comet-like activity of several small asteroids, including two members of the Themis dynamical family. Here we report infrared spectra of the asteroid 24 Themis which show that ice and organic compounds are not only present on its surface but also prevalent. Infrared spectral differences between it and other asteroids make 24 Themis unique so far, and our identification of ice and organics agrees with independent results that rule out other compounds as possible sources of the observed spectral structure. The widespread presence of surface ice on 24 Themis is somewhat unexpected because of the relatively short lifetime of exposed ice at this distance ( approximately 3.2 au) from the Sun. Nevertheless, there are several plausible sources, such as a subsurface reservoir that brings water to the surface through 'impact gardening' and/or sublimation.