Atmospheres, Climate, Weather Archives

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.

Zonal-mean zonal wind u and TEM streamfunction Ψ ∗ for northern hemisphere late summer and late autumn. Six contour levels are shown for Ψ ∗ at ±107 , ±108 and ±109 kg s−1 (negative contours dashed). Positive Ψ ∗ indicates clockwise overturning. -- astro-ph.EP

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Status Report, Titan

Equatorial Waves And Superrotation In The Stratosphere Of A Titan General Circulation Model

by Keith CowingJuly 13, 2023July 13, 2023

We investigate the characteristics of equatorial waves associated with the maintenance of superrotation in the stratosphere of a Titan general circulation model.

This image, acquired on April 8, 2011, with the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments on NASA’s Terra satellite, shows Saharan dust over the Bay of Biscay. A phytoplankton bloom makes the water appear bright green and blue. Sediment is likely contributing to some of the color, especially in coastal areas. Credits: NASA Earth Observatory image by Wanmei Liang, using MODIS data from NASA EOSDIS LANCE and GIBS/Worldview.

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Desert Worlds, Gaia - Planetary Perspectives, Plant Biology, Press Release, Water/Hycean Worlds & Oceanography

How Desert Dust Nourishes The Growth Of Phytoplankton In Earth’s Oceans

by Keith CowingJuly 10, 2023August 23, 2025

For the past few decades, scientists have been observing natural ocean fertilization events — episodes when plumes of volcanic ash, glacial flour, wildfire soot, and desert dust blow out onto […]

The probability P(L|TI) for TIs corresponding to LBHs as a function of the emergence rate of TIs in LBHs (units of Gyr−1 ). The vertical line is an estimate of the median value of this rate, based on the data from Earth -- astro-ph.EP

Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Intelligence & Language, Origin & Evolution of Life, Status Report, Water/Hycean Worlds & Oceanography

A Bayesian Analysis of Technological Intelligence In Land And Oceans

by Keith CowingJuly 10, 2023July 10, 2023

Current research indicates that (sub)surface ocean worlds essentially devoid of subaerial landmasses (e.g., continents) are common in the Milky Way, and that these worlds could host habitable conditions, thence raising […]

PDCSAP flux extracted from the short (2 minute) cadence data of the 24 sectors (1–13, 27, 29–37, 39) in which TOI-715 was observed. Light grey point show the 120 s exposures and the purple line shows the flux in 3minute bins. The transit events of TOI-715.01 are shown with the dark pink arrows and the locations of possible transits of TIC 271971130.02 are indicated with green arrows; we note that individual transits are not readily apparent by eye. -- astro-ph.EP

Astronomy & Telescopes, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Status Report

A 1.55 R⊕ Habitable-zone Planet Hosted By TOI-715, An M4 Star Near The Ecliptic South Pole

by Keith CowingJuly 8, 2023July 8, 2023

A new generation of observatories is enabling detailed study of exoplanetary atmospheres and the diversity of alien climates, allowing us to seek evidence for extraterrestrial biological and geological processes.

Result of planet evolution simulations in the orbital period–transit radius plane at 5 Gyr (left panel: energy-/recombination-limited model; right panel: hydrodynamic model). Each dot represents a planet which is coloured based on the fraction of its initial H/He envelope mass that was evaporated. Grey symbols indicate complete loss of the envelope, corresponding to sub-Neptunes that have evolved into super-Earths. The magenta lines show the fit to determine the slope α of the valley as represented by the largest super-Earth at a given period (i.e. the bottom of the valley). We note the shallower slope in the hydrodynamic model. The squares show two individual cases (one far planet in lilac, one close in black). Both start with identical initial conditions in the two models and are discussed in Sect. 4.2. They end up on different sides of the valley in the two models in a way to make the slope shallower in the hydrodynamic model. -- astro-ph.EP

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

Planetary Evolution With Atmospheric Photoevaporation II: Fitting The Slope Of The Radius Valley By Combining Boil-off And XUV-driven Escape

by Keith CowingJuly 7, 2023July 7, 2023

The Kepler satellite has revealed a gap between sub-Neptunes and super-Earths that atmospheric escape models had predicted as an evaporation valley.

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. -- astro-ph.EP

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

Analogous Response Of Temperate Terrestrial Exoplanets And Earth’s Climate Dynamics To Greenhouse Gas Supplement

by Keith CowingJuly 6, 2023July 6, 2023

Humanity is close to characterizing the atmospheres of rocky exoplanets due to the advent of JWST. These astronomical observations motivate us to understand exoplanetary atmospheres to constrain habitability.

Example of the progression of solid species of a simulation. The molar amount relative to the total molar content of the disk of each of the condensates included in the simulation is shown as a function of decreasing temperature in different line colours and styles, as denoted in the legend. See Appendix D for details on the included species. The simulation was run at a constant disk pressure of p = 10−4 bar and is based the solar elemental abundance pattern recommended by Lodders (2003). See Table B.2 for a summary of the simulation parameters. -- astro-ph.EP

AI - Data - Apps - Cybernetics, Astrochemistry, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Status Report

Revisiting Equilibrium Condensation And Rocky Planet Compositions: Introducing The ECCOplanets Code

by Keith CowingJuly 5, 2023July 5, 2023

We introduce ECCOplanets, an open-source Python code that simulates condensation in the protoplanetary disk.

Atmospheres, Climate, Weather, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Habitable Zones, Imaging & Spectroscopy, Status Report, Venus

Stability Of Nucleic Acid Bases In Concentrated Sulfuric Acid: Implications For The Habitability Of Venus’ Clouds

by Keith CowingJuly 3, 2023July 3, 2023

What constitutes a habitable planet is a frontier to be explored and requires pushing the boundaries of our terracentric viewpoint for what we deem to be a habitable environment.

Theoretical stability of subsurface water-ice with respect to diffusion for a) flat surfaces b) 30° pole-facing slopes, using a nominal near-surface humidity. The red curve is the 10% Water-Equivalent Hydrogen contour, which is a good proxy for the presence of water ice in the shallow subsurface (Pathare et al., 2018). White dots indicate exposed water ice along cliff scarps and impact craters as reported in Dundas, Becerra, et al. (2021); Dundas et al. (2023) White diamonds indicate exposed water ice along gullies (Khuller & Christensen, 2021). -- astro-ph.EP

Astrogeology, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Habitable Zones, Icy Worlds, Imaging & Spectroscopy, Mapping, Geodesy, Cartography, Bathymetry, Mars, Status Report

A Reappraisal of Near-Tropical Ice Stability on Mars

by Keith CowingJune 29, 2023June 29, 2023

Two arguments have suggested the presence of subsurface water ice at latitudes lower than 30° Mars.

Atmospheres, Climate, Weather

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

Equatorial Waves And Superrotation In The Stratosphere Of A Titan General Circulation Model

How Desert Dust Nourishes The Growth Of Phytoplankton In Earth’s Oceans

A Bayesian Analysis of Technological Intelligence In Land And Oceans

A 1.55 R⊕ Habitable-zone Planet Hosted By TOI-715, An M4 Star Near The Ecliptic South Pole

Planetary Evolution With Atmospheric Photoevaporation II: Fitting The Slope Of The Radius Valley By Combining Boil-off And XUV-driven Escape

Analogous Response Of Temperate Terrestrial Exoplanets And Earth’s Climate Dynamics To Greenhouse Gas Supplement

Revisiting Equilibrium Condensation And Rocky Planet Compositions: Introducing The ECCOplanets Code

Stability Of Nucleic Acid Bases In Concentrated Sulfuric Acid: Implications For The Habitability Of Venus’ Clouds

A Reappraisal of Near-Tropical Ice Stability on Mars

Astrobiology Graduate Conference (AbGradCon26) Update

ExMODE: A Comprehensive Resource For Extremophile Genomic And Functional Exploration

Mass Wasting On Mars

The Hill Sphere Transits of Beta Pictoris c and The Search for Another 1981-like Event

Sample Return Tech: Pre-impact Meteorite Strewn Field Predictions For Imminent Impactors And Meteorite Recovery