The Role of Ammonia in the Distribution of Volatiles in the Primordial Hydrosphere of Europa
The presence of a hydrosphere on Europa raises questions about its habitability, and studies of its volatile inventory can provide insight into its formation process. Different scenarios suggest that Europa's volatiles could be derived from cometary ices or devolatilized building blocks. The st...
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2025-01-01
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| Series: | The Planetary Science Journal |
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| Online Access: | https://doi.org/10.3847/PSJ/ad9925 |
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| author | Alizée Amsler Moulanier Olivier Mousis Alexis Bouquet Christopher R. Glein |
| author_facet | Alizée Amsler Moulanier Olivier Mousis Alexis Bouquet Christopher R. Glein |
| author_sort | Alizée Amsler Moulanier |
| collection | DOAJ |
| description | The presence of a hydrosphere on Europa raises questions about its habitability, and studies of its volatile inventory can provide insight into its formation process. Different scenarios suggest that Europa's volatiles could be derived from cometary ices or devolatilized building blocks. The study of post-accretion processes—in particular, the “open-ocean” phase that likely occurred before the formation of the icy crust—is crucial to distinguishing these origins, as this phase is likely to have influenced the volatile inventory. The abundance of ammonia in Europa's building blocks is also crucial for understanding the composition of its ocean and primordial atmosphere. We aim to investigate the ocean–atmosphere equilibrium during the post-accretion period by varying the ammonia fraction in the atmosphere. Our model evaluates the vapor–liquid equilibrium of water and volatiles, as well as the chemical equilibrium within the ocean, to study Europa's early hydrosphere. We explore two initial conditions: one in which Europa's hydrosphere originates from comet-like building blocks, and another in which it forms in equilibrium with a thick-and-CO _2 -rich atmosphere. In both scenarios, the initial ratio of accreted CO _2 to NH _3 determines the magnitude of their partial pressures in Europa's early atmosphere. If this ratio exceeds a certain threshold (set to 10 ^−4 in this study), the atmosphere will be CO _2 -rich; otherwise, it will be CO _2 -depleted, by multiple orders of magnitude. Overall, our work provides an initial assessment of the distribution of primordial volatiles in Europa's primitive hydrosphere and provides a baseline for interpreting data from the upcoming Europa Clipper mission. |
| format | Article |
| id | doaj-art-b502ca42eb8e4e2e8475d206488644c5 |
| institution | Kabale University |
| issn | 2632-3338 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
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| series | The Planetary Science Journal |
| spelling | doaj-art-b502ca42eb8e4e2e8475d206488644c52025-01-02T08:40:26ZengIOP PublishingThe Planetary Science Journal2632-33382025-01-0161110.3847/PSJ/ad9925The Role of Ammonia in the Distribution of Volatiles in the Primordial Hydrosphere of EuropaAlizée Amsler Moulanier0https://orcid.org/0009-0000-7492-1476Olivier Mousis1https://orcid.org/0000-0001-5323-6453Alexis Bouquet2https://orcid.org/0000-0001-8262-9678Christopher R. Glein3Aix-Marseille Université , CNRS, CNES, Institut Origines, LAM, Marseille, FranceAix-Marseille Université , CNRS, CNES, Institut Origines, LAM, Marseille, France; Institut Universitaire de France (IUF) , FranceAix-Marseille Université , CNRS, CNES, Institut Origines, LAM, Marseille, France; Aix-Marseille Université , CNRS, Institut Origines, PIIM, Marseille, FranceSpace Science Division, Space Sector, Southwest Research Institute , 6220 Culebra Road, San Antonio, TX 78238-5166, USAThe presence of a hydrosphere on Europa raises questions about its habitability, and studies of its volatile inventory can provide insight into its formation process. Different scenarios suggest that Europa's volatiles could be derived from cometary ices or devolatilized building blocks. The study of post-accretion processes—in particular, the “open-ocean” phase that likely occurred before the formation of the icy crust—is crucial to distinguishing these origins, as this phase is likely to have influenced the volatile inventory. The abundance of ammonia in Europa's building blocks is also crucial for understanding the composition of its ocean and primordial atmosphere. We aim to investigate the ocean–atmosphere equilibrium during the post-accretion period by varying the ammonia fraction in the atmosphere. Our model evaluates the vapor–liquid equilibrium of water and volatiles, as well as the chemical equilibrium within the ocean, to study Europa's early hydrosphere. We explore two initial conditions: one in which Europa's hydrosphere originates from comet-like building blocks, and another in which it forms in equilibrium with a thick-and-CO _2 -rich atmosphere. In both scenarios, the initial ratio of accreted CO _2 to NH _3 determines the magnitude of their partial pressures in Europa's early atmosphere. If this ratio exceeds a certain threshold (set to 10 ^−4 in this study), the atmosphere will be CO _2 -rich; otherwise, it will be CO _2 -depleted, by multiple orders of magnitude. Overall, our work provides an initial assessment of the distribution of primordial volatiles in Europa's primitive hydrosphere and provides a baseline for interpreting data from the upcoming Europa Clipper mission.https://doi.org/10.3847/PSJ/ad9925Planetary scienceGalilean satellitesOcean-atmosphere interactionsNatural satellite formationEuropa |
| spellingShingle | Alizée Amsler Moulanier Olivier Mousis Alexis Bouquet Christopher R. Glein The Role of Ammonia in the Distribution of Volatiles in the Primordial Hydrosphere of Europa The Planetary Science Journal Planetary science Galilean satellites Ocean-atmosphere interactions Natural satellite formation Europa |
| title | The Role of Ammonia in the Distribution of Volatiles in the Primordial Hydrosphere of Europa |
| title_full | The Role of Ammonia in the Distribution of Volatiles in the Primordial Hydrosphere of Europa |
| title_fullStr | The Role of Ammonia in the Distribution of Volatiles in the Primordial Hydrosphere of Europa |
| title_full_unstemmed | The Role of Ammonia in the Distribution of Volatiles in the Primordial Hydrosphere of Europa |
| title_short | The Role of Ammonia in the Distribution of Volatiles in the Primordial Hydrosphere of Europa |
| title_sort | role of ammonia in the distribution of volatiles in the primordial hydrosphere of europa |
| topic | Planetary science Galilean satellites Ocean-atmosphere interactions Natural satellite formation Europa |
| url | https://doi.org/10.3847/PSJ/ad9925 |
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