Year: 2024
Type: article
Abstract: We investigate the consequences of nonideal chemical interaction between silicate and overlying hydrogen-rich envelopes for rocky planets using basic tenets of phase equilibria. Based on our current understanding of the temperature and pressure conditions for complete miscibility of silicate and hydrogen, we find that the silicate-hydrogen binary solvus will dictate the nature of atmospheres and internal layering in rocky planets that garnered H 2 -rich primary atmospheres. The temperatures at the surfaces of supercritical magma oceans will correspond to the silicate-hydrogen solvus. As a result, the radial positions of supercritical magma ocean–atmosphere interfaces, rather than their temperatures and pressures, should reflect the thermal states of these planets. The conditions prescribed by the solvus influence the structure of the atmosphere, and thus the transit radii of sub-Neptunes. Separation of iron-rich metal to form metal cores in sub-Neptunes and super-Earths is not assured due to prospects for neutral buoyancy of metal in silicate melt induced by dissolution of H, Si, and O in the metal at high temperatures.
Source: The Planetary Science Journal
DOI: 10.3847/psj/ad8c40
Institution: University of California, Los Angeles
Language: English
Topic: Astro and Planetary Science
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,800
Awards: GUIDING QUESTION: HOW TO ACQUIRE SUSTAIN AND NURTURE LIFE-ESSENTIAL CHEMICAL INGREDIENTS ON THE SURFACE OF ROCKY PLANETS? BUILDING A HABITABLE ENVIRONMENT ON INNER SOLAR SYSTEM ROCKY SURFACES REQUIRES THE LIFE-ESSENTIAL CHEMICAL INGREDIENTS (C N O H S AND P) TO JOURNEY THROUGH A SERIES OF ASTRONOMICAL PLANETARY GEOLOGICAL AND GEOCHEMICAL PROCESSES DURING PLANET FORMATION AND EARLY PLANETARY EVOLUTION. HOWEVER IN MOST STUDIES ONLY ONE OR FEW OF THESE STEPS ARE INVESTIGATED IN ISOLATION AS CONDITIONS OF HABITABILITY AND THE CONSEQUENCES OF MULTIPLE PATHWAYS THAT MAY BE FEASIBLE ARE NOT RIGOROUSLY EXPLORED. SIMILARLY MOST STUDIES TRACKING THE IMPACT OF PREBIOTIC PROCESSES CONSIDERED THE ORIGIN OF WATER ALONE AND COMPREHENSIVE STUDIES ON A COMBINATION OF LIFE-ESSENTIAL ELEMENTS ARE LACKING. IN ORDER TO EVALUATE THE PATHWAYS THAT MAY LEAD TO EARLY HABITABLE CONDITIONS IN MULTIPLE PLANETARY SURFACES BUT SUSTENANCE ONLY IN A SUBSET AN INTERDISCIPLINARY APPROACH TO STUDY THE EARLY CYCLES OF ALL KEY INGREDIENTS ARE NECESSARY. THIS CAN 8 NAI NODE PROPOSAL AIMS TO CONSTRAIN THE PATHWAYS THAT LEAD TO THE ACQUISITION SUSTENANCE AND NURTURING OF THE LIFE-ESSENTIAL CHEMICAL ELEMENTS AT THE SURFACE AND NEAR-SURFACE ENVIRONMENTS OF ROCKY DIFFERENTIATED PLANETARY BODIES LEADING TO HABITABILITY AND POTENTIALLY DRIVING THE FORMATION OF PREBIOTICALLY-RELEVANT ORGANIC MOLECULE PRECURSORS WITHIN THE FIRST BILLION YEARS OF A PLANET S EVOLUTION. OUR TEAM MEMBERS BRING EXTENSIVE EXPERTISE IN ASTROPHYSICS GEOLOGY GEOCHEMISTRY GEOPHYSICS FLUID AND ATMOSPHERIC DYNAMICS CLIMATE SCIENCE AND ORGANIC CHEMISTRY; AN OVERARCHING GOAL IS TO TRACE THE LIFE-ESSENTIAL ELEMENTS FROM PROTOPLANETARY DISKS TO EARLY PREBIOTIC MOLECULES ON THE SURFACES OF ROCKY PLANETS WITH A PARTICULAR EMPHASIS ON THE FEEDBACKS AMONG INTERIOR SURFACE AND ATMOSPHERIC PROCESSES. WE WILL USE OBSERVATIONS FROM OUR OWN SOLAR SYSTEM IN TERMS OF COMPARATIVE PLANETOLOGY BUT WILL ALSO CONSTRUCT POSSIBLE PATHWAYS THAT MAY LEAD TO THERMO-CHEMICAL HABITABILITY WHICH CAN BE UTILIZED FOR EXPLORATION OF OTHER SOLAR SYSTEMS IN SEARCH FOR LIFE. THE PROPOSED RESEARCH COMPLEMENTS THE ACTIVITIES OF THE CAN 7 TEAMS BECAUSE NONE OF THE CURRENT TEAMS ARE INVESTIGATING THE CYCLES OF THE KEY INGREDIENTS DURING DIFFERENTIATION AND EARLY TECTONO-MAGMATIC AND GEOCHEMICAL EVOLUTION OF ROCKY PLANETS. OUR PROPOSAL WILL BRING IN THE UNIQUE INTERDISCIPLINARY PERSPECTIVE OF CYCLES OF KEY INGREDIENTS OF LIFE THROUGH DEEP TIME FROM GEOLOGIC PLANETARY GEOPHYSICAL AND GEOCHEMICAL PERSPECTIVES. GIVEN THE INTERDEPENDENT NATURE OF THE PROPOSED ACTIVITIES AMONG SEEMINGLY DISPARATE FIELDS OF RESEARCH THE SCOPE OF THIS PROPOSAL CAN ONLY BE SUPPORTED THROUGH AN INSTITUTE WITHOUT WALLS . RELEVANCE TO THE GOALS OF THE ASTROBIOLOGY PROGRAM: THE PROPOSED INVESTIGATION IS RELEVANT FOR SEVERAL OF THE GOALS OF THE ASTROBIOLOGY PROGRAM AS OUTLINED IN THE 2015 STRATEGY INCLUDING THE CENTRAL THEMES OF CONSTRUCTING HABITABLE WORLDS AND IDENTIFYING EXPLORING AND CHARACTERIZING ENVIRONMENTS FOR HABITABILITY AND BIOSIGNATURES . OUR PROPOSAL WILL DIRECTLY ADDRESS QUESTIONS SUCH AS HOW DOES THE STORY OF EARTH IN PARTICULAR IT S PAST INFORM US ABOUT HOW THE CLIMATES ATMOSPHERIC COMPOSITIONS INTERIORS AND BIOSPHERES OF PLANETS CAN CO-EVOLVE? BECAUSE OUR TEAM WILL STUDY THE INTERACTIONS OF INTERIOR ATMOSPHERE AND CLIMATE IN THE FIRST BILLION YEARS OF A ROCKY PLANETS EVOLUTION KEEPING IN MIND THE HISTORY OF THE EARTH AS AN ANALOG. OUR PROPOSAL WILL ALSO DIRECTLY ADDRESS QUESTIONS SUCH AS WHAT ARE THE FUNDAMENTAL INGREDIENTS AND PROCESSES THAT DEFINE A HABITABLE ENVIRONMENT? BECAUSE WE WILL TRACK THE FATE OF THE LIFE-ESSENTIAL ELEMENTS THROUGH THE FUNDAMENTAL PROCESSES OF PLANET FORMATION AND EARLY GEOLOGIC AND BIOGEOCHEMICAL EVOLUTION WITH THE GOAL OF OUTLINING POSSIBLE PATHS THAT ARE OR ARE NOT FAVORABLE IN FINALLY HARBORING THE COHNSP SPECIES AT THE PLANETARY SURFACES., Research - Carnegie Institution of Washington (2021)
OpenAlex ID: W4405193652