Mars is a primary target in the search for extraterrestrial life, and biologically informative organic molecules are key candidates for molecular biosignatures. However, the stability and transformation pathways of specific biological molecules under Mars-relevant surface stressors remain insufficiently constrained. Lycopene, a widespread carotenoid and possible precursor of geologically persistent carotenoid derivatives, was selected here as a model biomolecule. We used laboratory irradiation experiments to examine lycopene photodegradation in dry and solution states and in association with representative mineral matrices (quartz, montmorillonite, and jarosite) and oxychlorine salts (chlorite, chlorate, and perchlorate). UV–Vis spectroscopy and first-order kinetic fitting show that dry lycopene is markedly more stable than lycopene in ethyl acetate solution. Among the tested mineral matrices, montmorillonite provides the strongest protective effect, whereas quartz provides little buffering capacity. Oxychlorine effects are compound- and matrix-dependent: chlorite and chlorate generally accelerate degradation, whereas perchlorate shows a weaker, more context-dependent effect. Jarosite–oxychlorine mixtures produce particularly complex spectral changes, including rapid transformation in the jarosite–chlorite system and extended apparent preservation in the jarosite–perchlorate system. These results indicate that lycopene preservation under Mars-relevant conditions cannot be predicted from individual stressors alone and depends on coupled mineral–oxidant interactions. Because the experiments were conducted under terrestrial atmospheric conditions and product identities were not determined by molecular analyses, the results should be interpreted as comparative laboratory constraints rather than as direct estimates of Martian surface lifetimes.
We assess the potential of rocks from the Semail Ophiolite in the northern Al-Hajar Mountains of the southeast Arabian peninsula for use as lunar and Martian simulants. Ten rock samples were collected from the United Arab Emirates (UAE) and one from Oman, and we characterized their geochemistry, mineralogy, and spectral characteristics. We proposed mixing recipes of Semail rocks to synthetically make our unique simulants. Our synthetic mixtures’ effectiveness was evaluated according to goodness of model fit to existing lunar and Martian rock/soil data and Simulant Suitability Score (SSS) comparisons to well-known lunar and Martian simulants. Our lunar mare rock and soil simulants had the highest model fit (root-mean-square error less than 10) and highest SSS (78). Spectra of synthetic simulants and spectral indices of major minerals common to Semail samples, the Moon, and Mars (feldspar and pyroxenes) were also computed, serving as inputs to map suitable locations for simulant sourcing using Hyperion hyperspectral and Sentinel-2 multispectral imagery. Results indicate that regions of interest are found around southern Ras al-Khaimah, Ajman Emirate, and Dubai area of UAE. Our findings contribute to the efforts to make and characterize various simulants supporting planetary science and exploration.
Cassini-Huygens detected complex molecules exceeding several thousand atomic mass units in Titan’s atmosphere as well as energetic O+, OH+ and H2O+ ions in Saturn’s magnetosphere. The heavy molecules are suggested to be nitrogenous polycyclic aromatic hydrocarbons (PANH). The energetic ions are thought to penetrate into Titan’s atmosphere, potentially modifying the structure and chemistry of these macromolecules. This study investigates the composition of chemical species sputtered into the gas-phase once energetic ions impact said macromolecules. We have irradiated thin film samples of adenine (C5H5N5), a heterocyclic aromatic, at the HUN-REN Institute for Nuclear Research (ATOMKI) in Debrecen, Hungary. The experiments varied key parameters such as ion type (Neq+, Oq+, OHq+ and H2Oq+), energies (10 and 20 keV), temperatures (150 and 300 K) and fluences (up to 2 × 1015 ions . cm−2). In-situ quadrupole mass spectrometry measured the residual gas of the experimental chamber, analysing the material that was sputtered into the gas phase during irradiation. The deconvolution of these mass spectra was done using a Monte-Carlo approach, revealing a plethora of compounds including HCN, N2, C2N2, C2H3N, C3HN, CH2N2, NH3, C2H2 and CH4. Larger species like C5H5N5, C4H4N4 and C3H3N3 were only detected at the on-set of the irradiation. The sputtering of hydrocarbons and nitriles highlights a potential feedback mechanism in Titan’s atmosphere. The direct formation of CO and CO2 from PANH irradiation appears unlikely.
We investigate the dynamical evolution of asteroid fragments generated by impacts under the influence of planetary perturbations and the Yarkovsky effect. Based on an integrated approach that combines smoothed particle hydrodynamics (SPH) simulations of collisions with long-term N-body numerical simulation, we follow the orbital evolution of fragment populations for a maximum timespan of 100 million years (Myr). A series of models is numerically simulated to understand the role of the dynamical environment in the asteroid belt by varying resonance proximity. The results demonstrate that the orbital distribution of fragments is governed primarily by the proximity to a Jovian resonance and the Yarkovsky effect. Collisions occurring in dynamically dormant, non-resonant regions produce long-lived, compact asteroid families whose collisional signatures persist for at least hundreds of millions of years. In contrast, fragments generated near strong Jovian resonances experience rapid eccentricity and inclination excitations, chaotic diffusion, and efficient fragment loss. We specifically investigate the nature of collisions within the prominent Jovian 2:1 (Hecuba gap), 3:1 (Alinda group), 3:2 (Hilda region) resonances along with some weak resonances. Despite the intrinsically long-term stability of the Hilda population, the fragments generated by collisions at the 3:2 resonance undergo rapid resonant phase mixing and eccentricity diffusion in 3 out of 4 simulation runs, leading to the substantial loss of any identifiable family structures over tens of millions of years. The results demonstrate the importance of the Yarkovsky effect and the resonance-driven dynamics in shaping the dynamical structure of the collision-generated asteroid debris.
