Pub Date : 2025-10-19DOI: 10.1016/j.icarus.2025.116855
Elisa Dong , Catherine D. Neish , John E. Moores , Shigeru Wakita , Gareth S. Collins , Peter G. Brown , Ralph D. Lorenz , Benjamin Fernando , Mark P. Panning
We investigate the possibility of detecting airbursts in Titan’s atmosphere by considering their burst characteristics (height and energy release) and associated overpressure and surface displacement. To simulate the airbursts, we track the progression of meteors through the atmosphere using the Separate Fragments Model. The Separate Fragments Model outputs an energy release curve that can be used to locate the burst height and estimate the energy associated with the airburst. The overpressure at the surface beneath the airburst is estimated using empirical equations derived for Earth based nuclear tests and adapted to other planetary atmospheres. We estimate the coupled seismic displacement as compliance effects from point source impulses at the atmosphere and surface boundary. We find that the expected overpressure ranges between 1.1 – 53.2 Pa, and the peak velocity ranges between 0.1 and 72.3 , depending on the surface properties assumed for Titan. The larger signals may exceed the detection threshold of instrumentation onboard NASA’s Dragonfly mission, namely the Dragonfly Meteorological suite (DraGMet). For the nominal Dragonfly mission lifetime of 3 years, our current estimates suggest that less than one meteor of radius 1 m or greater will impact Titan. This suggests that if positive detections of airbursts via pressure sensor or seismometer do occur, we may need to revise our understanding of the impactor population distribution in the outer solar system.
{"title":"Signal characteristics of potential airbursts in Titan’s atmosphere","authors":"Elisa Dong , Catherine D. Neish , John E. Moores , Shigeru Wakita , Gareth S. Collins , Peter G. Brown , Ralph D. Lorenz , Benjamin Fernando , Mark P. Panning","doi":"10.1016/j.icarus.2025.116855","DOIUrl":"10.1016/j.icarus.2025.116855","url":null,"abstract":"<div><div>We investigate the possibility of detecting airbursts in Titan’s atmosphere by considering their burst characteristics (height and energy release) and associated overpressure and surface displacement. To simulate the airbursts, we track the progression of meteors through the atmosphere using the Separate Fragments Model. The Separate Fragments Model outputs an energy release curve that can be used to locate the burst height and estimate the energy associated with the airburst. The overpressure at the surface beneath the airburst is estimated using empirical equations derived for Earth based nuclear tests and adapted to other planetary atmospheres. We estimate the coupled seismic displacement as compliance effects from point source impulses at the atmosphere and surface boundary. We find that the expected overpressure ranges between 1.1 – 53.2 Pa, and the peak velocity ranges between 0.1 and 72.3 <span><math><mrow><mi>μ</mi><mspace></mspace><mi>m/s</mi></mrow></math></span>, depending on the surface properties assumed for Titan. The larger signals may exceed the detection threshold of instrumentation onboard NASA’s Dragonfly mission, namely the Dragonfly Meteorological suite (DraGMet). For the nominal Dragonfly mission lifetime of 3 years, our current estimates suggest that less than one meteor of radius 1 m or greater will impact Titan. This suggests that if positive detections of airbursts via pressure sensor or seismometer do occur, we may need to revise our understanding of the impactor population distribution in the outer solar system.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"445 ","pages":"Article 116855"},"PeriodicalIF":3.0,"publicationDate":"2025-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145417804","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-17DOI: 10.1016/j.icarus.2025.116842
Fabrizio Giordano , Yaël R.A. Bourgeois , Stéphanie M. Cazaux , Ferdinand F.J. Schrijer
In this study, plume experiments were conducted to mimic the thermodynamic conditions on Saturn’s moon, Enceladus. The icy moon’s subsurface ocean and cracks in the surface have been simulated using a liquid water reservoir and a narrow channel, while the low-pressure environment at Enceladus’ surface was achieved with a vacuum chamber. We aimed to examine how channel temperature affected the plume’s temperature, solid fraction and velocity, testing two models with differing wall temperatures: room temperature and near 0 °C. The colder setup better replicated Enceladus’ plume, producing a saturated flow in which nucleation of icy particles is possible. A conservative 1.5%–3% minimum solid fraction is estimated from measurements and modelling. Pitot-tube measurements indicated velocities around 400–500 m/s at the channel outlet. Flow temperature and velocity are closely correlated with wall temperature, indicating effective heat transfer. With a plume model based on the energy conservation law, we concluded that supersonic plume velocities observed on Enceladus cannot be achieved with straight channels, i.e. without requiring extreme expansion ratios. Additionally, the research provides evidence of the relationship between the crevasse’s expansion ratio and the temperatures of flow and crevasse walls.
{"title":"How Enceladus’ plume depends on the crevasse wall temperature: An experimental perspective","authors":"Fabrizio Giordano , Yaël R.A. Bourgeois , Stéphanie M. Cazaux , Ferdinand F.J. Schrijer","doi":"10.1016/j.icarus.2025.116842","DOIUrl":"10.1016/j.icarus.2025.116842","url":null,"abstract":"<div><div>In this study, plume experiments were conducted to mimic the thermodynamic conditions on Saturn’s moon, Enceladus. The icy moon’s subsurface ocean and cracks in the surface have been simulated using a liquid water reservoir and a narrow channel, while the low-pressure environment at Enceladus’ surface was achieved with a vacuum chamber. We aimed to examine how channel temperature affected the plume’s temperature, solid fraction and velocity, testing two models with differing wall temperatures: room temperature and near 0 °C. The colder setup better replicated Enceladus’ plume, producing a saturated flow in which nucleation of icy particles is possible. A conservative 1.5%–3% minimum solid fraction is estimated from measurements and modelling. Pitot-tube measurements indicated velocities around 400–500 m/s at the channel outlet. Flow temperature and velocity are closely correlated with wall temperature, indicating effective heat transfer. With a plume model based on the energy conservation law, we concluded that supersonic plume velocities observed on Enceladus cannot be achieved with straight channels, <em>i.e.</em> without requiring extreme expansion ratios. Additionally, the research provides evidence of the relationship between the crevasse’s expansion ratio and the temperatures of flow and crevasse walls.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"445 ","pages":"Article 116842"},"PeriodicalIF":3.0,"publicationDate":"2025-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145417802","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-17DOI: 10.1016/j.icarus.2025.116856
Juulia-Gabrielle Moreau , Argo Jõeleht , Anna Losiak , Meng-Hua Zhu , Jüri Plado
Sedimentary rocks often form the upper layers or the entire target rocks in impact events. Thermodynamic properties of sedimentary rocks related to porosity and water saturation affect the process of impact crater formation. The heterogeneous distribution of sedimentary facies can complicate the development and distribution of shock effects, especially in numerical modeling. This work focuses on the shock thermodynamic properties of carbonate rocks with differing porosity textures (e.g., isolated pores, interstitial porosity, elongated pores) and water saturation levels. Using mesoscale numerical modeling, we found that water saturation reduces shock temperatures compared to those in dry, porous carbonate rocks. The orientation of elongated pores and porosity lineations influences the shock temperature distribution and rock deformation at angles of 50–90° to the shock front. Additionally, due to complex shock wave interactions, interstitial porosity is key in creating temperature zonations around larger grains.
{"title":"Water saturation in texturally porous carbonate rocks: Shock thermodynamics and dampening of the shock","authors":"Juulia-Gabrielle Moreau , Argo Jõeleht , Anna Losiak , Meng-Hua Zhu , Jüri Plado","doi":"10.1016/j.icarus.2025.116856","DOIUrl":"10.1016/j.icarus.2025.116856","url":null,"abstract":"<div><div>Sedimentary rocks often form the upper layers or the entire target rocks in impact events. Thermodynamic properties of sedimentary rocks related to porosity and water saturation affect the process of impact crater formation. The heterogeneous distribution of sedimentary facies can complicate the development and distribution of shock effects, especially in numerical modeling. This work focuses on the shock thermodynamic properties of carbonate rocks with differing porosity textures (e.g., isolated pores, interstitial porosity, elongated pores) and water saturation levels. Using mesoscale numerical modeling, we found that water saturation reduces shock temperatures compared to those in dry, porous carbonate rocks. The orientation of elongated pores and porosity lineations influences the shock temperature distribution and rock deformation at angles of 50–90° to the shock front. Additionally, due to complex shock wave interactions, interstitial porosity is key in creating temperature zonations around larger grains.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"445 ","pages":"Article 116856"},"PeriodicalIF":3.0,"publicationDate":"2025-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145358789","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-11DOI: 10.1016/j.icarus.2025.116848
Amber Zandanel , Kai Gao , Simone Probst , Johan O.A. Robertsson , Carly M. Donahue
Current models of inner lunar geology have largely been inferred from the seismic experiments and observations performed during the Apollo missions that comprised a relatively small number of seismic instruments. Refining constraints on fundamental lunar relationships such as crust-mantle and mantle-core boundaries in the future will require seismic arrays spanning larger epicentral distances. A promising technology for installing dense seismic arrays with minimal human effort is distributed acoustic sensing (DAS), an approach that allows a single length of fiber optic cable to act as hundreds or thousands of sensors when coupled with a DAS interrogator. While terrestrial uses of DAS technology for seismic monitoring rely on burying the cable to maximize fidelity of seismic signal transmission to the fiber, digging meters of trench to bury optical fiber on lunar or planetary surfaces is logistically infeasible. To evaluate DAS signal attenuation due to surface deployment of cable in lunar regolith, we completed earthquake detection analyses that evaluated the sensitivity of an optic-fiber DAS system to seismic signals at different burial depths. We deployed a single-mode fiber in a 10-m open-bottom wooden box filled with a lunar regolith simulant (LRS) with fiber buried at different depths within the LRS and recorded signals for four regional and local earthquakes. The results were used to identify and evaluate signal attenuation in surface-deployed fiber compared to buried fiber in the LRS. Burial depth responses to active-source signals were also evaluated similar to previous studies characterizing DAS sensitivity of surface-deployed fiber. Atmospheric noise was minimal as the cable was deployed in an indoor environment; however, where observed, atmospheric and anthropogenic noise was filtered out using the same bandpass filtering used to identify earthquake events. We found that signal attenuation of the surface-deployed fiber compared to buried fiber was relatively high in active-source experiments but was not consistently observed in earthquake signals. That burial depth is not highly correlated to attenuation of the observed earthquake signals indicates that in a noise-limited environment, placing DAS-interrogated fiber directly at the regolith surface may be a promising deployment strategy to consider for sensing remote seismic signals during lunar exploration.
{"title":"Earthquake detection in a simulated lunar regolith using distributed acoustic sensing","authors":"Amber Zandanel , Kai Gao , Simone Probst , Johan O.A. Robertsson , Carly M. Donahue","doi":"10.1016/j.icarus.2025.116848","DOIUrl":"10.1016/j.icarus.2025.116848","url":null,"abstract":"<div><div>Current models of inner lunar geology have largely been inferred from the seismic experiments and observations performed during the Apollo missions that comprised a relatively small number of seismic instruments. Refining constraints on fundamental lunar relationships such as crust-mantle and mantle-core boundaries in the future will require seismic arrays spanning larger epicentral distances. A promising technology for installing dense seismic arrays with minimal human effort is distributed acoustic sensing (DAS), an approach that allows a single length of fiber optic cable to act as hundreds or thousands of sensors when coupled with a DAS interrogator. While terrestrial uses of DAS technology for seismic monitoring rely on burying the cable to maximize fidelity of seismic signal transmission to the fiber, digging meters of trench to bury optical fiber on lunar or planetary surfaces is logistically infeasible. To evaluate DAS signal attenuation due to surface deployment of cable in lunar regolith, we completed earthquake detection analyses that evaluated the sensitivity of an optic-fiber DAS system to seismic signals at different burial depths. We deployed a single-mode fiber in a 10-m open-bottom wooden box filled with a lunar regolith simulant (LRS) with fiber buried at different depths within the LRS and recorded signals for four regional and local earthquakes. The results were used to identify and evaluate signal attenuation in surface-deployed fiber compared to buried fiber in the LRS. Burial depth responses to active-source signals were also evaluated similar to previous studies characterizing DAS sensitivity of surface-deployed fiber. Atmospheric noise was minimal as the cable was deployed in an indoor environment; however, where observed, atmospheric and anthropogenic noise was filtered out using the same bandpass filtering used to identify earthquake events. We found that signal attenuation of the surface-deployed fiber compared to buried fiber was relatively high in active-source experiments but was not consistently observed in earthquake signals. That burial depth is not highly correlated to attenuation of the observed earthquake signals indicates that in a noise-limited environment, placing DAS-interrogated fiber directly at the regolith surface may be a promising deployment strategy to consider for sensing remote seismic signals during lunar exploration.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"445 ","pages":"Article 116848"},"PeriodicalIF":3.0,"publicationDate":"2025-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145322269","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-11DOI: 10.1016/j.icarus.2025.116845
Jose Daniel Castro-Cisneros , Renu Malhotra , Aaron J. Rosengren
We present a general analytic framework to assess whether impact ejecta launched from the surface of a satellite can escape the gravitational influence of the planet–satellite system and enter heliocentric orbit. Using a patched-conic approach and defining the transition to planetocentric space via the Hill sphere or sphere of influence, we derive thresholds for escape in terms of the satellite-to-planet mass ratio and the ratio of the satellite’s orbital speed to its escape speed. We identify three dynamical regimes for ejecta based on residual speed and launch direction. We complement this analysis with the circular restricted three-body problem, deriving a necessary escape condition from the Jacobi integral at and showing that it is consistent with the patched–conic thresholds. Applying our model to the Earth–Moon system reveals that all three outcomes — bound, conditional, and unbound — are accessible within a narrow range of launch speeds. This behavior is not found in other planetary satellite systems, but may occur in some binary asteroids. The framework also shows that the Moon’s tidal migration has not altered its propensity to produce escaping ejecta, reinforcing the plausibility of a lunar origin for some near-Earth asteroids.
{"title":"Analytical estimates for heliocentric escape of satellite ejecta","authors":"Jose Daniel Castro-Cisneros , Renu Malhotra , Aaron J. Rosengren","doi":"10.1016/j.icarus.2025.116845","DOIUrl":"10.1016/j.icarus.2025.116845","url":null,"abstract":"<div><div>We present a general analytic framework to assess whether impact ejecta launched from the surface of a satellite can escape the gravitational influence of the planet–satellite system and enter heliocentric orbit. Using a patched-conic approach and defining the transition to planetocentric space via the Hill sphere or sphere of influence, we derive thresholds for escape in terms of the satellite-to-planet mass ratio and the ratio of the satellite’s orbital speed to its escape speed. We identify three dynamical regimes for ejecta based on residual speed and launch direction. We complement this analysis with the circular restricted three-body problem, deriving a necessary escape condition from the Jacobi integral at <span><math><msub><mrow><mi>L</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> and showing that it is consistent with the patched–conic thresholds. Applying our model to the Earth–Moon system reveals that all three outcomes — bound, conditional, and unbound — are accessible within a narrow range of launch speeds. This behavior is not found in other planetary satellite systems, but may occur in some binary asteroids. The framework also shows that the Moon’s tidal migration has not altered its propensity to produce escaping ejecta, reinforcing the plausibility of a lunar origin for some near-Earth asteroids.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"445 ","pages":"Article 116845"},"PeriodicalIF":3.0,"publicationDate":"2025-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145321773","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
One of the frontier research fields of exoplanetary science is the study of the composition and variability of exoplanetary atmospheres. This field is now moving from the gas giant planets towards the smaller and colder telluric planets, and future instruments like ANDES will focus on the observations of the atmosphere of telluric planets in the habitable zone in reflected light. These future observations will possibly find variable signals due to the view of different hemispheres of the planet. Particularly, the strength of the signal may be linked to the thickness of the atmospheric layer probed, and therefore to the average altitude variations of the planetary surface, that are related to the global geodynamic evolution of the planet. To better prepare for the interpretation and exploitation of these future data, we used Mars as a Solar System analog of a spatially resolved telluric exoplanet. We observed the reflected light of Mars with the high-resolution near-infrared (NIR) spectrograph GIANO-B (widely used in exoplanetary atmospheric studies) during a 3 month period: we studied the spatial and temporal variations of the Martian CO2 signal using the least-squared deconvolution technique (LSD), to mimic as closely as possible the standard exoplanetary atmospheric analysis. We linked the variations found to the well-known Martian geological surface characteristics: we found a clear dependence of the strength of the CO2 signal with the thickness of the Martian atmospheric layer by comparing the retrieved CO2 signal with the altitudes of our pointings. The proposed strategy is promising: it proved to be effective on Mars and may shed light on the variations in the strength of atmospheric signal of telluric exoplanets.
{"title":"Probing the geological setting of exoplanets through atmospheric analysis: Using Mars as a test case","authors":"Monica Rainer , Evandro Balbi , Francesco Borsa , Paola Cianfarra , Avet Harutyunyan , Silvano Tosi","doi":"10.1016/j.icarus.2025.116847","DOIUrl":"10.1016/j.icarus.2025.116847","url":null,"abstract":"<div><div>One of the frontier research fields of exoplanetary science is the study of the composition and variability of exoplanetary atmospheres. This field is now moving from the gas giant planets towards the smaller and colder telluric planets, and future instruments like ANDES will focus on the observations of the atmosphere of telluric planets in the habitable zone in reflected light. These future observations will possibly find variable signals due to the view of different hemispheres of the planet. Particularly, the strength of the signal may be linked to the thickness of the atmospheric layer probed, and therefore to the average altitude variations of the planetary surface, that are related to the global geodynamic evolution of the planet. To better prepare for the interpretation and exploitation of these future data, we used Mars as a Solar System analog of a spatially resolved telluric exoplanet. We observed the reflected light of Mars with the high-resolution near-infrared (NIR) spectrograph GIANO-B (widely used in exoplanetary atmospheric studies) during a 3 month period: we studied the spatial and temporal variations of the Martian CO<sub>2</sub> signal using the least-squared deconvolution technique (LSD), to mimic as closely as possible the standard exoplanetary atmospheric analysis. We linked the variations found to the well-known Martian geological surface characteristics: we found a clear dependence of the strength of the CO<sub>2</sub> signal with the thickness of the Martian atmospheric layer by comparing the retrieved CO<sub>2</sub> signal with the altitudes of our pointings. The proposed strategy is promising: it proved to be effective on Mars and may shed light on the variations in the strength of atmospheric signal of telluric exoplanets.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"445 ","pages":"Article 116847"},"PeriodicalIF":3.0,"publicationDate":"2025-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145321756","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
<div><div>We have carried out simulations of permafrost liquid fraction to investigate the historical habitability of Martian and Antarctic ground ice. These simulations are based on the development of new soil freezing curves (SFCs) for example Martian and Antarctic soils, and expand upon our previous investigation of the temperature history of shallow Martian ice (Mellon et al., 2024). We considered the effects of salt doping on both soil types, using magnesium perchlorate, Mg(ClO<sub>4</sub>)<sub>2</sub>, as an endmember low-eutectic-temperature solute representative of Mars, and NaCl as a high-eutectic-temperature endmember, approximately representative of solutes in the Dry Valleys of Antarctica. We applied our SFCs to calculate the total liquid fraction, <em>S</em><sub><em>l</em></sub>, and maximum liquid vein diameter (or refugia diameter), <em>d</em><sub><em>r</em></sub>, in the icy permafrost under relevant Martian and Antarctic environmental conditions, building on previous work that considered habitability limits in the context of temperature, <em>T</em>, and water activity, <em>a</em><sub><em>w</em></sub>, only. We defined habitability thresholds of <em>S</em><sub><em>l</em></sub> ≥ 5 % and <em>d</em><sub><em>r</em></sub> ≥ 1 μm, then examined which of four habitability metrics (<em>T</em>, <em>a</em><sub><em>w</em></sub>, <em>S</em><sub><em>l</em></sub>, <em>d</em><sub><em>r</em></sub>) presents the dominant limitation to shallow ice habitability in the Martian icy-permafrost environment and in the perennially sub-freezing environments of the Antarctic Dry Valleys. We also re-evaluated optimal landing site selection for Mars life and habitability exploration missions in this context.</div><div>We find that, without salts, neither of the examined soils produce habitable values of <em>S</em><sub><em>l</em></sub> or <em>d</em><sub><em>r</em></sub> below ∼ − 3 °C based on pore-confinement effects alone. The addition of 1 dry wt% NaCl extends the occurrence of habitable values of <em>S</em><sub><em>l</em></sub> and <em>d</em><sub><em>r</em></sub> to the eutectic temperature of −21 °C; the addition of 1 dry wt% Mg(ClO<sub>4</sub>)<sub>2</sub> extends the occurrence of habitable values of <em>S</em><sub><em>l</em></sub> and <em>d</em><sub><em>r</em></sub> to the magnesium perchlorate eutectic temperature of −64 °C, well below the previously defined extreme metabolic limit of <em>T</em> = −40 °C. In both the Antarctic Dry Valley and Martian environments solute concentration is spatially variable and can occur locally at more or less than the 1 wt% scenarios we investigated. In the case of localized solute deficits, habitable <em>S</em><sub><em>l</em></sub> and <em>d</em><sub><em>r</em></sub> may not be achieved, even during summertime and high-obliquity temperature excursions. However, meeting the requirement of <em>d</em><sub><em>r</em></sub> > 1 μm and <em>S</em><sub><em>l</em></sub> > 5 % is surprisingly easy for silty to sandy soil
{"title":"Liquid Vein networks as habitats in ice-cemented ground on Earth and Mars: Effects of soil geometry and salts","authors":"H.G. Sizemore , M.T. Mellon , A.W. Rempel , C.P. McKay , J.L. Heldmann , C.R. Stoker , M.R. Perry","doi":"10.1016/j.icarus.2025.116828","DOIUrl":"10.1016/j.icarus.2025.116828","url":null,"abstract":"<div><div>We have carried out simulations of permafrost liquid fraction to investigate the historical habitability of Martian and Antarctic ground ice. These simulations are based on the development of new soil freezing curves (SFCs) for example Martian and Antarctic soils, and expand upon our previous investigation of the temperature history of shallow Martian ice (Mellon et al., 2024). We considered the effects of salt doping on both soil types, using magnesium perchlorate, Mg(ClO<sub>4</sub>)<sub>2</sub>, as an endmember low-eutectic-temperature solute representative of Mars, and NaCl as a high-eutectic-temperature endmember, approximately representative of solutes in the Dry Valleys of Antarctica. We applied our SFCs to calculate the total liquid fraction, <em>S</em><sub><em>l</em></sub>, and maximum liquid vein diameter (or refugia diameter), <em>d</em><sub><em>r</em></sub>, in the icy permafrost under relevant Martian and Antarctic environmental conditions, building on previous work that considered habitability limits in the context of temperature, <em>T</em>, and water activity, <em>a</em><sub><em>w</em></sub>, only. We defined habitability thresholds of <em>S</em><sub><em>l</em></sub> ≥ 5 % and <em>d</em><sub><em>r</em></sub> ≥ 1 μm, then examined which of four habitability metrics (<em>T</em>, <em>a</em><sub><em>w</em></sub>, <em>S</em><sub><em>l</em></sub>, <em>d</em><sub><em>r</em></sub>) presents the dominant limitation to shallow ice habitability in the Martian icy-permafrost environment and in the perennially sub-freezing environments of the Antarctic Dry Valleys. We also re-evaluated optimal landing site selection for Mars life and habitability exploration missions in this context.</div><div>We find that, without salts, neither of the examined soils produce habitable values of <em>S</em><sub><em>l</em></sub> or <em>d</em><sub><em>r</em></sub> below ∼ − 3 °C based on pore-confinement effects alone. The addition of 1 dry wt% NaCl extends the occurrence of habitable values of <em>S</em><sub><em>l</em></sub> and <em>d</em><sub><em>r</em></sub> to the eutectic temperature of −21 °C; the addition of 1 dry wt% Mg(ClO<sub>4</sub>)<sub>2</sub> extends the occurrence of habitable values of <em>S</em><sub><em>l</em></sub> and <em>d</em><sub><em>r</em></sub> to the magnesium perchlorate eutectic temperature of −64 °C, well below the previously defined extreme metabolic limit of <em>T</em> = −40 °C. In both the Antarctic Dry Valley and Martian environments solute concentration is spatially variable and can occur locally at more or less than the 1 wt% scenarios we investigated. In the case of localized solute deficits, habitable <em>S</em><sub><em>l</em></sub> and <em>d</em><sub><em>r</em></sub> may not be achieved, even during summertime and high-obliquity temperature excursions. However, meeting the requirement of <em>d</em><sub><em>r</em></sub> > 1 μm and <em>S</em><sub><em>l</em></sub> > 5 % is surprisingly easy for silty to sandy soil","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"445 ","pages":"Article 116828"},"PeriodicalIF":3.0,"publicationDate":"2025-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145462599","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Understanding Mars’ past environmental and climate characteristics greatly relies on the orbital detection of the numerous hydrous minerals present on the planet’s surface. These include clay minerals and sulfates, especially when they are found in close proximity to each other. However, remote sensing observations pose several challenges and limits to quantitative mineral observations. In addition, these minerals are often likely mixed with basaltic regolith originating from the planet’s volcanic crust, which affects their spectral signature. In this framework, measurements on analogs in a controlled laboratory environment are essential support to remote sensing data to perform quantitative spectral analysis. We conduct visible and near-infrared reflectance spectroscopy on binary and ternary intimate mixtures among (a) basalt, (b) Fe/Mg-clay minerals (nontronite, saponite), and (c) polyhydrated sulfate (hexahydrite) powders. Binary mixtures include combinations of (a)-(b) and (a)-(c), while ternary mixtures combine all three: (a)-(b)-(c). Absorption feature variations are assessed with measurements of band center, band area, and band depth. The results of binary mixtures indicate that basalt does not generally interfere with the position of diagnostic OH- and HO absorption features in the selected clays and sulfate samples but systematically reduces their band depth/area, leading to a possible underestimating of the hydrous component. Ternary mixing experiments highlight a strong and complex interaction between clay and sulfate endmembers, with variation in relative abundance causing the minima of their and OH- and HO absorption features to shift. Such shifts are significantly larger than the possible basalt-induced effect and show a step-like behavior, with minimum values clustering between two groups separated by 30 nm. The gap typically corresponds to 1:2 clay-to-sulfate ratio. This characteristic places important constraints on the relative abundance of clays and sulfates in mixed settings, independently of the basalt abundance. The results presented here provide substantial support in studying orbital detections of mixed clay/sulfate signatures. Moreover, they offer a more realistic interpretation framework in which the effects of Mars-like basaltic regolith are directly assessed.
{"title":"Visible-near infrared spectral behavior of Mars-analog clays, sulfate, and basalt mixtures","authors":"Beatrice Baschetti , Cristian Carli , Matteo Massironi , Fabio Tateo , Giulia Alemanno","doi":"10.1016/j.icarus.2025.116846","DOIUrl":"10.1016/j.icarus.2025.116846","url":null,"abstract":"<div><div>Understanding Mars’ past environmental and climate characteristics greatly relies on the orbital detection of the numerous hydrous minerals present on the planet’s surface. These include clay minerals and sulfates, especially when they are found in close proximity to each other. However, remote sensing observations pose several challenges and limits to quantitative mineral observations. In addition, these minerals are often likely mixed with basaltic regolith originating from the planet’s volcanic crust, which affects their spectral signature. In this framework, measurements on analogs in a controlled laboratory environment are essential support to remote sensing data to perform quantitative spectral analysis. We conduct visible and near-infrared reflectance spectroscopy on binary and ternary intimate mixtures among (a) basalt, (b) Fe/Mg-clay minerals (nontronite, saponite), and (c) polyhydrated sulfate (hexahydrite) powders. Binary mixtures include combinations of (a)-(b) and (a)-(c), while ternary mixtures combine all three: (a)-(b)-(c). Absorption feature variations are assessed with measurements of band center, band area, and band depth. The results of binary mixtures indicate that basalt does not generally interfere with the position of diagnostic OH- and H<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>O absorption features in the selected clays and sulfate samples but systematically reduces their band depth/area, leading to a possible underestimating of the hydrous component. Ternary mixing experiments highlight a strong and complex interaction between clay and sulfate endmembers, with variation in relative abundance causing the minima of their <span><math><mrow><mn>1</mn><mo>.</mo><mn>4</mn><mspace></mspace><mi>μ</mi><mi>m</mi></mrow></math></span> and <span><math><mrow><mn>1</mn><mo>.</mo><mn>9</mn><mspace></mspace><mi>μ</mi><mi>m</mi></mrow></math></span> OH- and H<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>O absorption features to shift. Such shifts are significantly larger than the possible basalt-induced effect and show a step-like behavior, with minimum values clustering between two groups separated by <span><math><mo>≥</mo></math></span> 30 nm. The gap typically corresponds to 1:2 clay-to-sulfate ratio. This characteristic places important constraints on the relative abundance of clays and sulfates in mixed settings, independently of the basalt abundance. The results presented here provide substantial support in studying orbital detections of mixed clay/sulfate signatures. Moreover, they offer a more realistic interpretation framework in which the effects of Mars-like basaltic regolith are directly assessed.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"445 ","pages":"Article 116846"},"PeriodicalIF":3.0,"publicationDate":"2025-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145321774","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-10DOI: 10.1016/j.icarus.2025.116840
Anastasiia Ovchinnikova, Ralf Jaumann, Sebastian H.G. Walter, Christoph Gross, Wilhelm Zuschneid, Frank Postberg
One of the challenges in reconstructing the water history of Jezero crater, Mars, is understanding the relationship between the deposition of the western and the northern deltas. Although the western delta appears to be less eroded and younger than the northern delta, multiple scenarios for their deposition have recently been proposed, including simultaneous formation of the northern and western fans/deltas. In our study, we combined topographical and compositional data to determine the origin of the low-calcium pyroxene (LCP) and olivine/carbonate units which were found within the northern and western deltas. We investigated whether these units are representative of the structure of the northern delta, and after analyzing the combined topographic and compositional profiles, no prominent stratigraphic correlations showing parallel layering were found. Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) data shows that the closest possible source of LCP is the western delta and the watershed of the western inlet. Therefore, we interpret the uppermost LCP unit within the northern delta as material transported from the western inlet which draped the already existing topography of the northern delta. That means that the northern delta (except for several locations between the delta and buttes) was already eroded to the current topography before the deposition of the LCP unit. To test this interpretation, we modeled the distance at which sediments transported from the western inlet through the channel on the western delta would be deposited. The results are consistent with the location of the LCP unit on top of the northern delta. That leads to the conclusion that there was a period when an active western inlet provided sediments which covered parts of the already eroded northern delta. Therefore, the main body of the Jezero's northern delta is older than the western delta but was partly covered with a relatively thin younger layer of material from the western inlet.
{"title":"Influence of the western inlet on the northern delta in Jezero crater, Mars: Topographic-compositional analysis and sediment transport modeling","authors":"Anastasiia Ovchinnikova, Ralf Jaumann, Sebastian H.G. Walter, Christoph Gross, Wilhelm Zuschneid, Frank Postberg","doi":"10.1016/j.icarus.2025.116840","DOIUrl":"10.1016/j.icarus.2025.116840","url":null,"abstract":"<div><div>One of the challenges in reconstructing the water history of Jezero crater, Mars, is understanding the relationship between the deposition of the western and the northern deltas. Although the western delta appears to be less eroded and younger than the northern delta, multiple scenarios for their deposition have recently been proposed, including simultaneous formation of the northern and western fans/deltas. In our study, we combined topographical and compositional data to determine the origin of the low-calcium pyroxene (LCP) and olivine/carbonate units which were found within the northern and western deltas. We investigated whether these units are representative of the structure of the northern delta, and after analyzing the combined topographic and compositional profiles, no prominent stratigraphic correlations showing parallel layering were found. Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) data shows that the closest possible source of LCP is the western delta and the watershed of the western inlet. Therefore, we interpret the uppermost LCP unit within the northern delta as material transported from the western inlet which draped the already existing topography of the northern delta. That means that the northern delta (except for several locations between the delta and buttes) was already eroded to the current topography before the deposition of the LCP unit. To test this interpretation, we modeled the distance at which sediments transported from the western inlet through the channel on the western delta would be deposited. The results are consistent with the location of the LCP unit on top of the northern delta. That leads to the conclusion that there was a period when an active western inlet provided sediments which covered parts of the already eroded northern delta. Therefore, the main body of the Jezero's northern delta is older than the western delta but was partly covered with a relatively thin younger layer of material from the western inlet.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"445 ","pages":"Article 116840"},"PeriodicalIF":3.0,"publicationDate":"2025-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145358801","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-08DOI: 10.1016/j.icarus.2025.116843
Z.H. Luo , K.C. Chow , J. Xiao
Northern cap-edge dust storms during spring are major dust activities in the non-dusty season of Mars. In this study, we apply a parameterization scheme to the Mars climate model MarsWRF to simulate the dust activities in the northern cap-edge region. Consistent with observations, the simulation result shows a period of weak dust activities in the northern mid spring (Ls 30°-60°) and a stronger period just before the northern summer solstice, with a pause of dust activities between these two periods. The results of the sensitivity experiments suggest that the sublimation flow associated with cap recession is important to the occurrence of dust lifting but its effect on dust lifting near the cap edge could be different in different periods. The sublimation flow generally reduces the dust lifting flux in mid spring while enhances dust lifting at the end of spring. Three specific areas that are prone to dust lifting have also been identified. The simulation results suggest that the locations of the preferred dust lifting areas and the pause between the two active periods are possibly related to the topography in northern high latitudes.
{"title":"Characteristics and dynamics of spring-time northern cap-edge dust activities simulated by a Mars climate model","authors":"Z.H. Luo , K.C. Chow , J. Xiao","doi":"10.1016/j.icarus.2025.116843","DOIUrl":"10.1016/j.icarus.2025.116843","url":null,"abstract":"<div><div>Northern cap-edge dust storms during spring are major dust activities in the non-dusty season of Mars. In this study, we apply a parameterization scheme to the Mars climate model MarsWRF to simulate the dust activities in the northern cap-edge region. Consistent with observations, the simulation result shows a period of weak dust activities in the northern mid spring (Ls 30°-60°) and a stronger period just before the northern summer solstice, with a pause of dust activities between these two periods. The results of the sensitivity experiments suggest that the sublimation flow associated with cap recession is important to the occurrence of dust lifting but its effect on dust lifting near the cap edge could be different in different periods. The sublimation flow generally reduces the dust lifting flux in mid spring while enhances dust lifting at the end of spring. Three specific areas that are prone to dust lifting have also been identified. The simulation results suggest that the locations of the preferred dust lifting areas and the pause between the two active periods are possibly related to the topography in northern high latitudes.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"445 ","pages":"Article 116843"},"PeriodicalIF":3.0,"publicationDate":"2025-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145321757","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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