atmosphere Archives

Comparison between sources and sinks of H2 on rocky planets around M dwarfs. The grey areas show the range of escape rates depending on the type of the host star. The dark grey area is for a planet that locates at the 1-AU equivalent distance, while the light grey area is for a planet that locates 2.6 times farther away (i.e., receiving 7 times less irradiation). The outgassing rates encapsulate the plausible range from a highly reduced mantle (informed by Figure 1), with the lower bound corresponding to xH = 0.005 wt % and t −1 scaling, and the higher bound corresponding to xH = 0.02 wt % and t −2 scaling. The rate of serpentinization is a very generous upper limit (Section 4). -- astro-ph.EP

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones

Narrow Loophole for H2-dominated Atmospheres On Habitable Rocky Planets Around M Dwarfs

by Keith CowingApril 27, 2023April 27, 2023

Habitable rocky planets around M dwarfs that have H2-dominated atmospheres, if they exist, would permit characterizing habitable exoplanets with detailed spectroscopy using JWST, owing to their extended atmospheres and small […]

Mixing ratios for the major species in the Archean Earth-like (ARE) atmospheres and temperature profiles. Each line represents a self-consistent Earth-like atmosphere orbiting a stellar host. Earlier-type M dwarf hosts are lighter and later-type M dwarf hosts are darker. The dashed blue line represents profiles for the Earth orbiting the Sun for comparison. -- astro-ph.EP

Astrochemistry, Astronomy & Telescopes, Atmospheres, Climate, Weather, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy

There’s More To Life Than O2: Simulating the Detectability Of A Range Of Molecules For Ground-based high-resolution Spectroscopy Of Transiting Terrestrial Exoplanets

by Keith CowingApril 24, 2023April 27, 2023

Within the next decade, atmospheric O2 on Earth-like M dwarf planets may be accessible with visible–near-infrared, high spectral resolution extremely large ground-based telescope (ELT) instruments.

Climatic elements on three planets. (a)–(c) Temporal- and zonal-mean temperature (color shading) and zonal-mean zonal winds (contour lines) on Earth, on the rapidly rotating tidally locked terrestrial planet, and on the slowly rotating tidally locked terrestrial planet; (d)–(f) same as (a)–(c) but for deviations of temporal- and zonal-mean geopotential height from the global means (color shading), and mass stream functions (contour lines, in units of 1010 kg s−1 ). Note that the ranges of color bars in panels (d), (e), and (f) are different. Panels (a), (b), (d) and (e) are shown in the standard coordinates, and (c) and (f) are shown in the tidally locked coordinates. SP and AP are the substellar point and the antistellar point, respectively. -- astro-ph.EP

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Habitable Zones

Lorenz Energy Cycle: Another Way to Understand the Atmospheric Circulation on Tidally Locked Terrestrial Planets

by Keith CowingApril 24, 2023April 27, 2023

In this study, we employ and modify the Lorenz energy cycle (LEC) framework as another way to understand the atmospheric circulation on tidally locked terrestrial planets.

Top panel: example wavelength sector showing the model contribution from CO only. The model is shown at simulated resolution (grey, sampled every ˚Angstrom) and after being convolved with the observed point spread function and rebinned onto the detector’s wavelength grid (black). Middle panel: visualisation of our method for detecting CO sub-band structure. Red and blue portions indicate wavelengths that are in-band or out-of-band, respectively. Note these wavelength selections are refined in Figure 4. Bottom panel: model contributions per molecule, where H2O is the only significant molecular absorber in this wavelength sector other than CO. -- astro-ph.EP

Astrochemistry, Astronomy & Telescopes, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets

Detection of Carbon Monoxide’s 4.6 Micron Fundamental Band Structure In WASP-39b’s Atmosphere With JWST NIRSpec G395H

by Keith CowingApril 24, 2023April 27, 2023

Carbon monoxide (CO) is predicted to be the dominant carbon-bearing molecule in giant planet atmospheres, and, along with water, is important for discerning the oxygen and therefore carbon-to-oxygen ratio of […]

Column density maps for H2 (top left), H (top right), and O (bottom) from the torus model (Smith et al. 2019, 2022) in a plane through Jupiter and corresponding to the viewing geometry of the first torus-centered exposure le2oa1010 (Table 1) from 2020. For O, the tori of Europa-genic (left) and Io-genic (right) material are shown separately. Jupiter (large black circle) is centered and Io (white, behind Jupiter) and Europa (black) are shown by the smaller disks to the right (west of Jupiter). The densities are higher closer to the moons (here, west of Jupiter) and the HST/COS observations scanned over the densest regions of the Europa-genic neutrals from 8.0 RJ to 12.5 RJ. (Note that the viewing geometry in Figure 1 corresponds to an 1.5-hour earlier exposure). -- astro-ph.EP

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Europa, Habitable Zones, Icy Worlds, Imaging & Spectroscopy, Status Report, Water/Hycean Worlds & Oceanography

Constraints On Europa’s Water Group Torus From HST/COS Observations

by Keith CowingApril 18, 2023April 18, 2023

In-situ plasma measurements as well as remote mapping of energetic neutral atoms around Jupiter provide indirect evidence that an enhancement of neutral gas is present near the orbit of the […]

Mass–radius for USP planets, with mass–radius measurements better than 25 per cent from http://www.astro.keele.ac.uk/jkt/tepcat/ and for our USP TESS candidates (see Table 1), colour coded by their equilibrium temperature. Two-layer models from Zeng et al. (2016) are displayed with different lines and colours. ‘Earth-like’ here means a composition of 30 per cent Fe and 70 per cent MgSiO3, whereas ‘100 per cent Rock’ means a composition of 100 per cent MgSiO3. Earth and Venus are identified in this plot as pale blue and orange circles, respectively -- astro-ph.EP

Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report

Surface Pressure Impact On Nitrogen-dominated USP Super-Earth Atmospheres

by Keith CowingApril 18, 2023April 18, 2023

In this paper, we compare the chemistry and the emission spectra of nitrogen-dominated cool, warm, and hot ultra-short-period (USP) super-Earth atmospheres in and out of chemical equilibrium at various surface […]

The sequence of events leading to formation of water, light elements in metal, and increases in oxygen fugacity for Earth’s progenitor embryos in this work. Stage 1 is the embryo where surface temperatures are too high to retain primary atmospheres of hydrogen. Stage 2 is the initial condition for our calculations in which the molten embryos accrete and retain primary atmospheres of H2. Metalsilicate differentiation may have already begun at this stage. Stage 3 is the result of chemical equilibration of the silicate and metal melts with the evolved atmospheres. Annotations show the changes in oxygen fugacity and metal density deficits. Reactions shown are simplifications of the full set, for illustration purposes. Two or more such embryos combine to form the final Earth. -- astro-ph.EP

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Origin & Evolution of Life, Status Report, Water/Hycean Worlds & Oceanography

Earth Was Shaped By Primordial Hydrogen Atmospheres

by Keith CowingApril 17, 2023April 17, 2023

Earth’s water, intrinsic oxidation state, and metal core density are fundamental chemical features of our planet. Studies of exoplanets provide a useful context for elucidating the source of these chemical […]

An artist's impression of the 'light curve' produced by a star passing behind Titan. The spike at the center of the light curve represents the central flash produced by Titan's atmosphere acting as a lens and refracting the starlight toward a single focal point. Credit: NASA/ESA/C.Carreau

Astrochemistry, Astronomy & Telescopes, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Imaging & Spectroscopy, Press Release, Titan

Using Stars To Study Titan’s Atmosphere

by Keith CowingApril 11, 2023April 11, 2023

With its thick atmosphere and mysterious weather patterns, Saturn’s largest moon, Titan, is an alien world ripe with discovery potential.

Molecular volume mixing ratios comparing the equilibrium and disequilibrium abundances as a function of pressure altitude. The significant presence of CO in the disequilibrium model is highlighted with a thick curve. Molecules are roughly grouped into color families and labels are constrained to the same y-coordinate in both panels. Additional species noticeably affected by the disequilibrium chemistry include N2, NH3, CO2, and HCN. -- astro-ph.EP

Astronomy & Telescopes, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

The Infrared Colors Of 51 Eridani b: Micrometereoid Dust Or Chemical Disequilibrium?

by Keith CowingApril 11, 2023April 11, 2023

We reanalyze near-infrared spectra of the young extrasolar giant planet 51 Eridani b which was originally presented in (Macintosh et al. 2015) and (Rajan et al. 2017) using modern atmospheric […]

Surface temperature as a function of incoming instellation for different hydrogen-helium inventories. The introduction of layers with convective inhibition when the moisture content at the bottom of the atmosphere (BOA) is high enough (orange region) causes a rapid increase in surface temperature (and moisture content). Once the bottom of the atmosphere is pure steam (pink region), the atmosphere becomes optically thick and increasing surface temperature is no longer linked with an increase in cooling, causing a runaway state. -- astro-ph.EP

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Habitable Zones, Status Report, Water/Hycean Worlds & Oceanography

The Runaway Greenhouse Effect on Hycean Worlds

by Keith CowingApril 11, 2023April 11, 2023

Hycean worlds are a proposed subset of sub-Neptune exoplanets with substantial water inventories, liquid surface oceans and extended hydrogen-dominated atmospheres that could be favourable for habitability.

atmosphere

Narrow Loophole for H2-dominated Atmospheres On Habitable Rocky Planets Around M Dwarfs

There’s More To Life Than O2: Simulating the Detectability Of A Range Of Molecules For Ground-based high-resolution Spectroscopy Of Transiting Terrestrial Exoplanets

Lorenz Energy Cycle: Another Way to Understand the Atmospheric Circulation on Tidally Locked Terrestrial Planets

Detection of Carbon Monoxide’s 4.6 Micron Fundamental Band Structure In WASP-39b’s Atmosphere With JWST NIRSpec G395H

Constraints On Europa’s Water Group Torus From HST/COS Observations

Surface Pressure Impact On Nitrogen-dominated USP Super-Earth Atmospheres

Earth Was Shaped By Primordial Hydrogen Atmospheres

Using Stars To Study Titan’s Atmosphere

The Infrared Colors Of 51 Eridani b: Micrometereoid Dust Or Chemical Disequilibrium?

The Runaway Greenhouse Effect on Hycean Worlds

Impact Crater Hydrothermal Systems Support Rapid Microbial Enrichment and Diverse Metabolic Potential

Photometric and Spectroscopic Observations of Comet 2P/Encke’s Nucleus in the Mid-Infrared Wavelength Region

A New Method Maps An Exoplanet’s True Shape

Wavefront-Conditioned Photon Measurements for Exoplanet Spectroscopy: Contrast Limits and Conditional Gains

ExoPAG 35 – Early Career Talks Invitation