Atmospheres, Climate, Weather Archives

Posterior distributions from MCMC fits to the dayside spectrum (orange) and the transmission spectrum (green). For each model, the x-axis shows the metallicity distribution. For the cloudy model we plot the sedimentation efficiency fsed on the y-axis and for the haze models we plot the logarithm of the haze formation rate η (in g cm−2 s −1 ) on the y-axis. The three isodensity lines denote the 1-, 2-, and 3-σ-limits of the posteriors. An extra monochromatic offset parameter was used to fit transmission spectra. Correlations with that parameter are not displayed here. None of the posterior samples here have χ 2 ν < 1.6 for both spectra simultaneous -- astro-ph.EP

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

Probing Reflection From Aerosols with the near-infrared dayside spectrum of WASP-80b

by Keith CowingJuly 29, 2023July 29, 2023

The presence of aerosols is intimately linked to the global energy budget and composition of planet atmospheres.

This artist's illustration shows a planet (dark silhouette) passing in front of the red dwarf star AU Microscopii. The planet is so close to the eruptive star a ferocious blast of stellar wind and blistering ultraviolet radiation is heating the planet's hydrogen atmosphere, causing it to escape into space. Four times Earth's diameter, the planet is slowly evaporating its atmosphere, which stretches out linearly along its orbital path. This process may eventually leave behind a rocky core. The illustration is based on measurements made by the Hubble Space Telescope. Credits: NASA, ESA, and Joseph Olmsted (STScI)

Astronomy & Telescopes, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Habitable Zones, Press Release, Space Weather & Heliophysics

A Young Super-Earth Orbiting Red Dwarf AU Microscopii Is Evaporating

by Keith CowingJuly 29, 2023July 29, 2023

A young planet whirling around a petulant red dwarf star is changing in unpredictable ways orbit-by-orbit. It is so close to its parent star that it experiences a consistent, torrential […]

Top: the oxygen A-band observation using two dualons in the arrays: dualon1 data are displayed in black solid line and dualon2 in blue. Middle: the zoomed-in region shows the features of the chained spectrum both the absorption feature embedded on top of the instrumental profiles. The signal of the dualon2 is scaled up by a factor of 1.5. Bottoms: the zoomed-in region from the middle panel shows the shift between the two dualons. -- astro-ph.IM

Astronomy & Telescopes, Atmospheres, Climate, Weather, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report

First On-sky Results Of A FIOS Prototype, A Fabry Perot Based Instrument For Oxygen Searches

by Keith CowingJuly 28, 2023July 28, 2023

The upcoming Extremely Large Telescopes (ELTs) are expected to have the collecting area required to detect potential biosignature gases such as molecular oxygen, O2, in the atmosphere of terrestrial planets […]

Satellite image of Sahara dust storm moving over the Atlantic Ocean. -- NASA

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biophysics, Biosignatures & Paleobiology, Press Release

Sahara Dust Can Enhance Removal Of Methane

by Keith CowingJuly 26, 2023July 26, 2023

The study by Maarten van Herpen et al., entitled “Photocatalytic Chlorine Atom Production on Mineral Dust-Sea Spray Aerosols over North Atlantic,” was funded in part by the NGO Spark Climate […]

Energy deposition E0 in J m−1 for individual meteoroids of a given mass descending through Titan’s atmosphere. The inversion at lower altitudes occurs as the particles begin to both decelerate and lose mass, resulting in a decreasing amount of energy being deposited. -- astro-ph.EP

Atmospheres, Climate, Weather, Biochemistry & Organic Chemistry, Biophysics, Biosignatures & Paleobiology, Icy Worlds, Impact events, Meteorites & Asteroids, Press Release, Titan

Shock Synthesis of Organic Molecules by Meteoroids in the Atmosphere of Titan

by Keith CowingJuly 21, 2023July 21, 2023

Thermochemical modeling and shock-tube experiments show that shocks applied to N2/CH4 gas mixtures can synthesize organic molecules. Sufficiently large, hypersonic meteoroids entering the atmosphere of Saturn’s moon Titan should therefore […]

Simulated composition and climate of the Hadean atmosphere after a 1.58 × 1021 kg impactor that produces 7.0 bars of H2 once vaporized ocean water condenses. We use the Table 2 model parameters. The blue shaded region labeled “hot steam atmosphere”, also called Phase 2 in Figure 1, is simulated by the kinetics-climate model described in Appendix B. After this time-period, during Phase 3 of a post-impact atmosphere, we evolve the atmosphere with 1-D photochemical-climate model (Appendix C), which maintains 0.018 bar of CH4 between 4×103 and ∼ 106 years. Dashed lines are referenced to the right-hand axis. “HCN rainout” is HCN molecules raining out in droplets of water. “HCCCN haze rainout” is the rainout rate of HCCCN incorporated into particles formed from the reaction C4H + HCCCN → polymer. CH4 and N2 photochemistry generates HCN and HCCCN for about one million years until H2 escapes to space. -- astro-ph.EP

Atmospheres, Climate, Weather, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Impact events, Origin & Evolution of Life, Status Report

Origin Of Life Molecules In The Atmosphere After Big Impacts On The Early Earth

by Keith CowingJuly 19, 2023July 19, 2023

The origin of life on Earth would benefit from a prebiotic atmosphere that produced nitriles, like HCN, which enable ribonucleotide synthesis. However, geochemical evidence suggests that Hadean air was relatively […]

Solutions for the various heating scenarios with 𝑎 = 250 km. The top three rows show zonally-averaged temperature 𝑇, zonal flow speed 𝑈, meridional streamfunction Ψ(𝜙, 𝑧) = ∫ 𝑧 −𝐻tot 𝜌(𝜙, 𝑧′ )𝑉 (𝜙, 𝑧′ ) × (2𝜋(𝑎 + 𝑧 ′ ) cos 𝜙) 𝑑𝑧′ , where 𝜙 denotes latitude, 𝑧 denotes altitude, −𝐻tot is the altitude of the seafloor and 𝑉 and 𝜌 are meridional speed and density. Ψ > 0 indicates clockwise circulation. The last row (panel d1-4) shows the vertically-integrated meridional ocean heat transport F (𝜙) = ∫ −𝐻 −𝐻tot 𝜌(𝜙, 𝑧′ )𝑉 (𝜙, 𝑧′ )𝑇 (𝜙, 𝑧′ ) × (2𝜋(𝑎 + 𝑧 ′ ) cos 𝜙) 𝑑𝑧′ . F > 0 if heat is transport northward. From the left to the right column show solutions with 𝑄0 = 0, 𝑄0 = Hcond 𝑓deep ≈ 𝑄𝑐/3, 𝑄0 = 𝑄𝑐 and 𝑄0 = 5𝑄𝑐, respectively, where 𝑄𝑐 = 0.21 W/m2 . Panel (e2) shows the mid-level vertical velocity field for the core-heating scenario -- astro-ph.EP

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

The Modulation Effect Of Ice Thickness Variations On Convection In Icy Ocean Worlds

by Keith CowingJuly 19, 2023July 19, 2023

It has been long puzzling whether the ice thickness variations observed on Enceladus can be sustained sorely by a polar-amplified bottom heating. The key to this question is to understand […]

Top: Top-of-atmosphere number flux from the Sun and TRAPPIST-1 (left y-axis). Also co-plotted are the photolysis cross-sections of CO2 (right abscissa). Bottom: CO2 cross-sections weighted by the stellar emission of TRAPPIST-1 and the Sun. The bluer spectrum of TRAPPIST-1 increases the weight of shortwave σCO2 , which is larger, driving an increase in σUV,g. -- astro-ph.EP

Atmospheres, Climate, Weather, Biochemistry & Organic Chemistry, Exoplanets, -moons, -comets, Habitable Zones, Status Report

A Re-Appraisal of CO/O2 Runaway On Habitable Planets Orbiting Low-Mass Stars

by Keith CowingJuly 19, 2023July 19, 2023

Efforts to spectrally characterize the atmospheric compositions of temperate terrestrial exoplanets orbiting M-dwarf stars with the James Webb Space Telescope (JWST) are now underway. Key molecular targets of such searches […]

Median temperature (K) differences between high and low pCO2 scenarios and median wind speeds (m s−1) for each scenario for Earth-like (a, c) and TRAPPIST-1e (b, d) ExoCAM simulations at (a, b) upper and (c, d) near-surface levels. Black and green quivers represent the high and low pCO2 scenarios, respectively. Using the Wilcoxon Rank-Sum test, lime and magenta-filled contours for wind speed and temperature represent areas not statistically significant at the 5% level, respectively. -- The Hebrew University of Jerusalem

Atmospheres, Climate, Weather, Biochemistry & Organic Chemistry, Exoplanets, -moons, -comets, Habitable Zones, Press Release, TRAPPIST-1

Greenhouse Gas Supplement Increases Warming And Alters Circulation Patterns On Earth and Earth-like Exoplanets

by Keith CowingJuly 13, 2023July 13, 2023

With the launch of the James Webb Space Telescope (JWST), the study of exoplanetary atmospheres and their potential habitability reached new heights. A team of researchers led by Dr. Assaf […]

Similar to Figure 6, but here Tint is held constant at a value of 40 K, and cloud-top pressure (large grid cells) and water abundance (smaller embedded grid cells — see zoom-in panel at lower left) are varied as the two parameters of interest. In the absence of impact of clouds, the large grid cells should look identical to Figure 6, mirrored over the upper-left to lower-right diagonal (e.g. see the upper left-hand large grid cells). The presence of low-pressure (high-altitude) clouds alter the degree of degeneracy between spectra, as detailed in the text. -- astro-ph.EP

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

Where Are The Water Worlds?: Self-Consistent Models of Water-Rich Exoplanet Atmospheres

by Keith CowingJuly 13, 2023July 13, 2023

It remains to be ascertained whether sub-Neptune exoplanets primarily possess hydrogen-rich atmospheres or whether a population of H2O-rich “water worlds” lurks in their midst.

Atmospheres, Climate, Weather

Probing Reflection From Aerosols with the near-infrared dayside spectrum of WASP-80b

A Young Super-Earth Orbiting Red Dwarf AU Microscopii Is Evaporating

First On-sky Results Of A FIOS Prototype, A Fabry Perot Based Instrument For Oxygen Searches

Sahara Dust Can Enhance Removal Of Methane

Shock Synthesis of Organic Molecules by Meteoroids in the Atmosphere of Titan

Origin Of Life Molecules In The Atmosphere After Big Impacts On The Early Earth

The Modulation Effect Of Ice Thickness Variations On Convection In Icy Ocean Worlds

A Re-Appraisal of CO/O2 Runaway On Habitable Planets Orbiting Low-Mass Stars

Greenhouse Gas Supplement Increases Warming And Alters Circulation Patterns On Earth and Earth-like Exoplanets

Where Are The Water Worlds?: Self-Consistent Models of Water-Rich Exoplanet Atmospheres

ExoClock Unlocked: A Project To Increase Public Participation In Exoplanet Research

Galápagos Hydrothermal Vents Join Third 100 IUGS Geological Heritage Site Listing

Best Bulk Bennu (B3): Elemental Compositions Of Aggregate Samples From Asteroid Bennu K.

The Neptunian Ridge Through The Lens Of TESS

Sulfur Dioxide Sulfide (SSO2): The Elusive Isovalent Analogue of Sulfur Trioxide (SO3)