Volatiles Archives

Condensation curves serve as a tool for prediction building block composition as a function of conditions in the PSN. Here they are compared to the predicted cooling curve of the PSN where the giant planets may have formed. (left) Equilibrium curves for pure condensates (dashed lines) where species are in the gas phase above the curves. (right) Scenario for clathrate formation including a combination of condensate, hydrate (NH3–H2O), and clathrate formation (X–5.75H2Oor X–5.67H2O; solid lines), along with crystallization of pure CO2 condensate (dotted line). (Mousis et al. 2020) reprinted with permission © Springer. -- astro-ph.EP

Astrochemistry, Astrogeology, Biosignatures & Paleobiology, Comets and Asteroids, Icy Worlds, Imaging & Spectroscopy, Press Release

Volatiles In Small Bodies

by Keith CowingJuly 24, 2025July 24, 2025

Small bodies are the remnant building blocks from the time when the planets formed and migrated to their current positions.

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Habitable Zones, Mars, Status Report

A Hybrid Origin for the Martian Atmosphere

by Keith CowingFebruary 24, 2025February 24, 2025

The Martian isotopic record displays a dichotomy in volatile compositions. Interior volatiles from the mantle record a chondritic heritage (e.g., H, N, Kr, Xe) whereas the atmospheric reservoir of Kr […]

Our target sample, showing the distribution of fit planet size, temperature, and stellar Teff . Red points are our primary sample, white points are known companions to our targets, dashed lines connect planets orbiting the same target star, and light gray points are other known exoplanets. The histogram at right shows how our planet sizes (red) compare to the intrinsic occurrence of sub-Neptunes (gray, Fulton & Petigura 2018). Noted that these best-fit radii differ from the TESS-reported radii plotted in Fig. 2c. -- astro-ph.EP

Astrogeology, Exoplanets, -moons, -comets, Icy Worlds, Imaging & Spectroscopy, Status Report

OrCAS: Origins, Compositions, and Atmospheres of Sub-neptunes. I. Survey Definition

by Keith CowingNovember 29, 2024November 29, 2024

Sub-Neptunes – volatile-rich exoplanets smaller than Neptune – are intrinsically the most common type of planet known.

Schematic overview of coupled redox-atmosphere-interior evolution model, PACMAN-P. The model is initialized with a completely molten mantle, and the solidification radius, rs, evolves from the core-mantle boundary to the surface, rp, as the planet cools. At each timestep, we calculate multiphase thermochemical equilibrium between C, H, O, and Fe-bearing species to find the mantle redox state and the partitioning of volatiles between the magma ocean and the atmosphere. Surface climate, Tsurf, is calculated using a radiative-convective model given atmospheric volatile inventories. Under highly reducing conditions created by large H2 envelopes, the reaction of H2 with the silicate magma ocean produces metallic iron, that is either sequestered in the core or remains in the mantle (two endmember assumptions). Atmospheric escape is either XUV-limited or diffusion limited depending on stratospheric composition, and under the former regime we calculate the hydrodynamic drag of O and CO. -- astro-ph.EP

Astrogeology, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Status Report, TRAPPIST-1

The Erosion Of Large Primary Atmospheres Typically Leaves Behind Substantial Secondary Atmospheres On Temperate Rocky Planets

by Keith CowingOctober 1, 2024October 1, 2024

Exoplanet exploration has revealed that many–perhaps most–terrestrial exoplanets formed with substantial H2-rich envelopes, seemingly in contrast to solar system terrestrials, for which there is scant evidence of long-lived primary atmospheres. […]

Ratio of the cumulative collision rate of comets with the Earth analog to the cumulative collision rate of carbonaceous asteroids with the Earth analog. The cumulative collision rates are reset at the time of the Moon-forming impact; and the ratio is set to 0 when the cumulative collision rates of carbonaceous asteroids (denominator) equals 0. So the dashed line shows the number of collisions with comets relative to the number of collisions with carbonaceous asteroids (weighted by their respective numbers in our simulations) on Earth since gas disk dispersal until the Moon-forming impact; and the solid line shows the same relative number since the Moon-forming impact until the end of the simulation. While cumulative collision rates of comets with Earth are ≃ 4 orders of magnitude smaller than those of carbonaceous asteroids before the Moon-forming impact, they are between 3 and 7 orders of magnitude smaller after the Moon-forming impact. In 30% of our simulations, there is about 1 comet every 103 carbonaceous asteroids colliding with the Earth after the Moon-forming event, which is consistent with the total cometary mass expected during late accretion. -- astro-ph.EP

Astrochemistry, Astrogeology, Biogeochemical Cycles & Geobiology, Comets and Asteroids, Extinction events, Gaia - Planetary Perspectives, Habitable Zones, Impact events, Meteorites & Asteroids, Moon, Origin & Evolution of Life, Status Report, Water/Hycean Worlds & Oceanography

Crash Chronicles: Relative Contribution From Comets and Carbonaceous Asteroids to Earth’s Volatile Budget In The Context of an Early Instability

by Keith CowingJune 25, 2024June 25, 2024

Recent models of solar system formation suggest that a dynamical instability among the giant planets happened within the first 100 Myr after disk dispersal, perhaps before the Moon-forming impact. As […]

In this image of the Serpens Nebula from NASA’s James Webb Space Telescope, astronomers found a grouping of aligned protostellar outflows within one small region (the top left corner). Serpens is a reflection nebula, which means it’s a cloud of gas and dust that does not create its own light, but instead shines by reflecting the light from stars close to or within the nebula. NASA, ESA, CSA, K. Pontoppidan (NASA’s Jet Propulsion Laboratory) and J. Green (Space Telescope Science Institute).

Astrochemistry, Astronomy & Telescopes, Imaging & Spectroscopy, Interstellar, Press Release

Astrochemistry Update: First of Its Kind Detection Made in Striking New Webb Image

by Keith CowingJune 21, 2024June 21, 2024

For the first time, a phenomenon astronomers have long hoped to directly image has been captured by NASA’s James Webb Space Telescope’s Near-Infrared Camera (NIRCam). In this stunning image of […]

Comparison of peak planetesimal mean temperature, 𝑇¯ peak,pl, for simulations where Ψ = 0.25 in the core model. Similarly to Fig. 8 we see that there is a strong dependence on planetesimal temperature and 26Al enrichment but an extremely weak dependence on 60Fe enrichment and planetesimal temperature. This shows that in the case of the core model 60Fe has a weak dependence. -- astro-ph.EP

Astrochemistry, Astrogeology, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Status Report

Devolatilization Of Extrasolar Planetesimals By 60Fe And 26Al Heating

by Keith CowingFebruary 14, 2024February 14, 2024

Whilst the formation of Solar system planets is constrained by meteoritic evidence, the geophysical history of low-mass exoplanets is much less clear. The bulk composition and climate states of rocky […]

Schematic contours of H, C, and N speciation determined by Raman spectroscopy in basaltic glasses synthesized in piston-cylinder experiments at 1–2 GPa and 1,400°C–1,600°C, shown as a function of fO2 (relative to the IW buffer) and H content (as equivalent H2O, wt. %). Raman and FTIR measurements are from Hirschmann (2012), Armstrong et al. (2015), Dalou et al. (2019, 2022), and Grewal et al. (2020). Blank areas represent conditions at which literature data are currently lacking. This figure demonstrates that H, C, and N on their own may be present as multiple species at a given fO2 or water content, and that they combine to form different molecules in natural and synthetic glasses. fO2 of Earth and Mars formation are indicated. Sulfur speciation is not shown because the effect of H on S speciation has not yet been determined at fO2 relevant to magma ocean conditions. -- astro-ph.EP

Astrochemistry, Astrogeology, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Status Report, Water/Hycean Worlds & Oceanography

The Distribution Of Volatile Elements During Rocky Planet Formation

by Keith CowingDecember 3, 2023December 2, 2023

Core segregation and atmosphere formation are two of the major processes that redistribute the volatile elements-hydrogen (H), carbon (C), nitrogen (N), and sulfur (S)-in and around rocky planets during their […]

Astrochemistry, Astrogeology, Comets and Asteroids, Impact events, Status Report

A Race Against The Clock: Constraining The Timing Of Cometary Bombardment Relative To Earth’s Growth

by Keith CowingSeptember 11, 2023September 18, 2025

Comets are considered a potential source of inner solar system volatiles, but the timing of this delivery relative to that of Earth’s accretion is still poorly understood.

Top: Abundance and temperature-pressure profiles for a 3 M⊕, 600 K equilibrium temperature planet, with 0.1% soot, orbiting an M-dwarf star. Even under the harsh UV irradiation environment of the host star, high abundances of methane (thick brown line) persist to high altitude and low pressure. A combination of methane photolysis in the upper atmosphere, vertical mixing, and thermochemistry give rise to significant quantities of higher-order hydrocarbons such as C2H2, C2H4, and C2H6, Subsequent photolysis and polymerization reactions result in the formation of hydrocarbon haze (thick dashed red line). Bottom: The resulting transmission spectrum (orange line) of this planet is shaped considerably by haze with some strong methane features permeating through the haze at longer wavelengths. The teal line shows the transmission spectrum of the same planet but with the haze opacity artificially removed, while the transparent colored line shows these data at a spectral resolution of R=1,000. -- astro-ph.EP

Astrochemistry, Atmospheres, Climate, Weather, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Status Report, Water/Hycean Worlds & Oceanography

Exoplanet Volatile Carbon Content as a Natural Pathway for Haze Formation

by Keith CowingMay 9, 2023May 9, 2023

We explore terrestrial planet formation with a focus on the supply of solid-state organics as the main source of volatile carbon.

Volatiles

Volatiles In Small Bodies

A Hybrid Origin for the Martian Atmosphere

OrCAS: Origins, Compositions, and Atmospheres of Sub-neptunes. I. Survey Definition

The Erosion Of Large Primary Atmospheres Typically Leaves Behind Substantial Secondary Atmospheres On Temperate Rocky Planets

Crash Chronicles: Relative Contribution From Comets and Carbonaceous Asteroids to Earth’s Volatile Budget In The Context of an Early Instability

Astrochemistry Update: First of Its Kind Detection Made in Striking New Webb Image

Devolatilization Of Extrasolar Planetesimals By 60Fe And 26Al Heating

The Distribution Of Volatile Elements During Rocky Planet Formation

A Race Against The Clock: Constraining The Timing Of Cometary Bombardment Relative To Earth’s Growth

Exoplanet Volatile Carbon Content as a Natural Pathway for Haze Formation

Thousands Of Planets Are Hidden In This Photo

Nearby “Super Earth” May Be A Better Candidate For Life Than Previously Thought

How A Giant Planet Survived Its Star’s Death

Improving Exoplanet Mass Characterisation With Bayesian Model Selection Using The Learned Harmonic Mean Estimator

Unveiling Complex Chemistry In Planet-forming Disks With The SKAO