Ceres’ Internal Evolution

Castillo‐Rogez, Julie; Bland, P. A.

doi:10.1017/9781108856324.014

Cited by 3 publications

(5 citation statements)

References 111 publications

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“…Further production of clathrates may occur after the release of volatiles into the ocean through metamorphism. (Castillo-Rogez & Bland 2022). Given 57% rock by volume and that Pluto's radius is 1188.3 km (Stern et al 2015), the rocky core has a radius of ∼980 km.…”

Section: Accretional Composition and Differentiationmentioning

confidence: 99%

Timing and Abundance of Clathrate Formation Control Ocean Evolution in Outer Solar System Bodies: Challenges of Maintaining a Thick Ocean within Pluto

Courville,

Castillo-Rogez,

Daswani

et al. 2023

Planet. Sci. J.

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Clathrate hydrates may represent a sizable fraction of material within the icy shells of Kuiper Belt objects and icy moons. They influence the chemical and thermal evolution of subsurface oceans by locking volatiles into the ice shell and by providing more thermal insulation than pure water ice. We model the formation of these crystalline compounds in conditions relevant to outer solar system objects, using Pluto as an example. Although Pluto may have hosted a thick ocean in its early history, Pluto’s overall heat budget is probably insufficient to preserve liquid today if its outer shell is pure water ice. One previously proposed reconciliation is that Pluto’s ocean has a winter jacket: an insulating layer of methane clathrate hydrates. Unfortunately, assessments of the timing, quantity, and type of clathrate hydrates forming within planetary bodies are lacking. Our work quantifies the abundance of clathrate-forming gases present in Pluto’s ocean from accreted ices and volatiles released during thermal metamorphism throughout Pluto’s history. We find that if Pluto formed with the same relative abundances of ices found in comets, then a buoyant layer of mixed methane and carbon dioxide clathrate hydrates may form above Pluto’s ocean, though we find it insufficient to preserve a thick ocean today. In general, our study provides methodology for predicting clathrate formation in ocean worlds, which is necessary to predict the evolution of the ocean’s composition and whether a liquid layer remains at present.

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Section: Accretional Composition and Differentiationmentioning

confidence: 99%

Timing and Abundance of Clathrate Formation Control Ocean Evolution in Outer Solar System Bodies: Challenges of Maintaining a Thick Ocean within Pluto

Courville,

Castillo-Rogez,

Daswani

et al. 2023

Planet. Sci. J.

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“…This would return samples from the ice deposits in Occator crater which may also be one of the places where salty water from the subsurface muddy ocean is exposed to space (Castillo-Rogez, 2022). (Carter, 2022) (Castillo-Rogez, 2022.…”

Section: Which Of Course Is Not Ethically Acceptable But What Do You Do?mentioning

confidence: 99%

“…We may return samples from Ceres in the late 2030s. We will need to take precautions to protect Earth in case there is life in those samples (Carter, 2022) (Castillo-Rogez, 2022.…”

Section: See Abovementioning

confidence: 99%

NASA must protect Earth's biosphere even if Mars samples hold mirror life – motivating planetary protection with new scenarios like mirror life - survey of recent research relevant to a Mars sample return - and how to keep Earth's biosphere 100% safe with a miniature telerobotic lab above GEO, and protect other biospheres 100% with sterile robotic explorers

Walker¹

2023

Preprint

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In the late 2020s to 2030s, China, and NASA / ESA and Japan plan to return samples from Mars. We need to keep Earth’s biosphere safe from any Martian microbes. Japan’s agency JAXA has the simplest mission, to return samples from the top few centimeters of Mars’s innermost moon Phobos. JAXA can safely return unsterilized samples without any precautions, because any microbes already withstood ejection from Mars, most recently, 700,000 years ago. Then on Phobos they were sterilized similarly to martian meteorites arriving at Earth today from that ancient impact.JAXA warned this meteorite argument is not valid for samples from the Martian surface. NASA’s draft EIS incorrectly says any life from Jezero crater can get here faster and better protected in a meteorite than in a sample tube. Surface dirt and dust can’t get here at all.NASA’s EIS also proposes to return its samples to a Biosafety Level 4 facility. However, the European Space Foundation study in 2012 set size limits well beyond capabilities of a BSL-4 and indeed beyond any current air filter capabilities.We can avoid all these issues and keep Earth 100% safe by sterilizing samples before they get here, with the equivalent of a few hundred million years of Mars surface ionizing radiation. This has virtually no effect on geology, while terrestrial contamination in Perseverance’s samples makes most astrobiology impossible.We can greatly increase science value with contamination free samples in a sterile container returned to a martian gravity centrifuge in an unmanned satellite above GEO, to start Sagan’s “vigorous program of unmanned exobiology”. This is a review of central results in planetary protection literature, with new worst case scenarios such as mirror life, to encourage space agencies to ensure Earth’s biosphere is adequately protected when they return samples from Mars.

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“…However, it is possible that only a fraction of Ceres' rock was involved in aqueous alteration processes. If large particles (a few millimeters across; e.g., calcium aluminum inclusions and chondrules) gravitationally settled into Ceres' interior rapidly during the differentiation phase Castillo-Rogez & Bland 2021), then aqueous alteration of these particles and their contribution to the early ocean composition may be limited. On the other hand, organic and more volatile-rich material, which tends to be associated with the fine-grained matrix in chondrites, would be physically fractionated as a result of longer settling timescales relative to the larger particles or would stay in suspension for a long time (e.g., Bland & Travis 2017).…”

Section: Contribution Of Ceres Exploration To Ocean World Sciencementioning

confidence: 99%

“…In that model, a thick ocean remains until present, and the mantle temperature remains below 100°C throughout Ceres' history. Pros and cons for that model are summarized in Castillo-Rogez & Bland (2021). The main open question is whether fine rock particles would remain in suspension for billions of years and avoid processes such as hydrolysis (Sirono 2013) and flocculation (e.g., Kranck 1973).…”

Section: Long-term Persistence Of Liquid Water In the Absence Of Tida...mentioning

confidence: 99%

Science Drivers for the Future Exploration of Ceres: From Solar System Evolution to Ocean World Science

et al. 2022

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Dawn revealed that Ceres is a compelling target whose exploration pertains to many science themes. Ceres is a large ice- and organic-rich body, potentially representative of the population of objects that brought water and organics to the inner solar system, as well as a brine-rich body whose study can contribute to ocean world science. The Dawn observations have led to a renewed focus on planetary brine physics and chemistry based on the detection of many landforms built from brines or suspected to be emplaced via brine effusion. Ceres’ relative proximity to Earth and direct access to its surface of evaporites that evolved from a deep brine reservoir make this dwarf planet an appealing target for follow-up exploration. Future exploration, as described here, would address science questions pertinent to the evolution of ocean worlds and the origin of volatiles and organics in the inner solar system.

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Ceres’ Internal Evolution

Cited by 3 publications

References 111 publications

Timing and Abundance of Clathrate Formation Control Ocean Evolution in Outer Solar System Bodies: Challenges of Maintaining a Thick Ocean within Pluto

Timing and Abundance of Clathrate Formation Control Ocean Evolution in Outer Solar System Bodies: Challenges of Maintaining a Thick Ocean within Pluto

Science Drivers for the Future Exploration of Ceres: From Solar System Evolution to Ocean World Science

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