Key Atmospheric Signatures for Identifying the Source Reservoirs of Volatiles in Uranus and Neptune

Abstract

We investigate the enrichment patterns of several delivery scenarios of the volatiles to the atmospheres of ice giants, having in mind that the only well constrained determination made remotely, i.e. the carbon abundance measurement, suggests that their envelopes possess highly supersolar metallicities, i.e. close to two orders of magnitude above that of the protosolar nebula. In the framework of the core accretion model, only the delivery of volatiles in solid forms (amorphous ice, clathrates, pure condensates) to these planets can account for the apparent supersolar metallicity of their envelopes. In contrast, because of the inward drift of icy particles through various snowlines, all mechanisms invoking the delivery of volatiles in vapor forms predict subsolar abundances in the envelopes of Uranus and Neptune. Alternatively, even if the disk instability mechanism remains questionable in our solar system, it might be consistent with the supersolar metallicities observed in Uranus and Neptune, assuming the two planets suffered subsequent erosion of their H-He envelopes. The enrichment patterns derived for each delivery scenario considered should be useful to interpret future in situ measurements by atmospheric entry probes.

arXiv commentAccepted for publication in Space Science Reviews

References in corpus (43)

• The chemical composition of the Sun
• Rapid growth of gas-giant cores by pebble accretion
• A simple model for the evolution of the dust population in protoplanetary disks
• Forming the cores of giant planets from the radial pebble flux in protoplanetary discs
• Separating gas-giant and ice-giant planets by halting pebble accretion
• Evolution of protoplanetary disks: Constraints from DM Tauri and GM Aurigae
• Pebble isolation mass --- scaling law and implications for the formation of super-Earths and gas giants
• Planetesimal formation starts at the snow line
• Interior Models of Uranus and Neptune
• Chemical enrichment of giant planets and discs due to pebble drift
• The evolution of gravitationally unstable protoplanetary disks: fragmentation and possible giant planet formation
• Jupiter's composition suggests its core assembled exterior to the N2 snowline
• Methane on Uranus: The case for a compact CH4 cloud layer at low latitudes and a severe CH4 depletion at high-latitudes based on re-analysis of Voyager occultation measurements and STIS spectroscopy
• NOTE: Explaining why the Uranian satellites have equatorial prograde orbits despite the large planetary obliquity
• The D/H ratio in the atmospheres of Uranus and Neptune from Herschel PACS observations
• The Formation of Jupiter's Diluted Core by a Giant Impact
• Determination of the minimum masses of heavy elements in the envelopes of Jupiter and Saturn
• How cores grow by pebble accretion I. Direct core growth
• Clathration of Volatiles in the Solar Nebula and Implications for the Origin of Titan's atmosphere
• Jupiter's formation and its primordial internal structure
• Accretion of Uranus and Neptune from inward-migrating planetary embryos blocked by Jupiter and Saturn
• Volatile inventories in clathrate hydrates formed in the primordial nebula
• Neptune's Atmospheric Composition from AKARI Infrared Spectroscopy
• Deep Atmosphere Composition, Structure, Origin, and Exploration, with Particular Focus on Critical in situ Science at the Icy Giants
• First results of Herschel/PACS observations of Neptune
• Carbon-rich planet formation in a solar composition disk
• Mid-Infrared Spectroscopy of Uranus from the Spitzer Infrared Spectrometer: 1. Determination of the Mean Temperature Structure of the Upper Troposphere and Stratosphere
• The Heavy Element Composition of Disk Instability Planets Can Range From Sub- to Super-Nebular
• Methane depletion in both polar regions of Uranus inferred from HST/STIS and Keck/NIRC2 observations
• Probable detection of hydrogen sulphide (H${}_2$S) in Neptune's atmosphere
• The Formation of Uranus & Neptune: Challenges and Implications For Intermediate-Mass Exoplanets
• Neptune at Summer Solstice: Zonal Mean Temperatures from Ground-Based Observations 2003-2007
• Mid-Infrared Spectroscopy of Uranus from the Spitzer Infrared Spectrometer: 2. Determination of the Mean Composition of the Upper Troposphere and Stratosphere
• Effect of Non-Adiabatic Thermal Profiles on the Inferred Compositions of Uranus and Neptune
• Bifurcation in the history of Uranus and Neptune: the role of giant impacts
• Thermochemistry and vertical mixing in the tropospheres of Uranus and Neptune: How convection inhibition can affect the derivation of deep oxygen abundances
• External Photoevaporation of the Solar Nebula: Jupiter's Noble Gas Enrichments
• A protosolar nebula origin for the ices agglomerated by Comet 67P/Churyumov-Gerasimenko
• Models of the Collisional Damping Scenario for Ice Giant Planets and Kuiper Belt Formatio
• Jupiter's formation in the vicinity of the amorphous ice snowline
• Latitudinal variation in the abundance of methane (CH4) above the clouds in Neptune's atmosphere from VLT/MUSE Narrow Field Mode Observations
• Steamworlds: atmospheric structure and critical mass of planets accreting icy pebbles
• No compelling evidence for clathrate hydrate formation under interstellar medium conditions over laboratory timescales

Cited by in corpus (4)

• The Fundamental Connections Between the Solar System and Exoplanetary Science
• The Exoplanet Perspective on Future Ice Giant Exploration
• The deep composition of Uranus and Neptune from in situ exploration and thermochemical modeling
• Evolution of steam worlds: energetic aspects