Atmospheres, Climate, Weather Archives

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Icy Worlds, Mars, Press Release

Ice-Exposing Impact Crater Surrounded by Polygon Terrain On Mars

by Keith CowingNovember 4, 2023November 4, 2023

The ice-exposing impact crater at the center of this image is an example of what scientists look for when mapping places where future astronauts should land on Mars.

Constraining the surface heterogeneities of a host star. a. A simulated 3.3-d full rotation curve of TRAPPIST-1 (black line) featuring nine transits of six planets (coloured lines). b. A snapshot of the spot distribution at the last rotational phase of the simulation shown in panel a, with the transit chords of planets b, c, d, and e. c. Contaminated transmission spectra for the same transit train of planets b–e (coloured lines). A nominal planet radius of 1 R⊕ (dashed gray line) is used for each planet to ease comparisons of the TLS effect for each planet. d. The residual stellar contamination signals for the simulated transits of planets c–e (coloured lines), after correcting for the TLS effect using the in-transit signal from planet b. A median-subtracted model of an atmosphere (see Figure 2) is shown for comparison (gray dashed line). e. Close-up view of the transit profiles for the four-planet transit train, highlighting repeated occultations of the same active regions by planets b and d as well as c and e, whose transit chords overlap in this simulation. -- astro-ph.EP

Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report, TRAPPIST-1

A Roadmap To The Efficient And Robust Characterization Of Temperate Terrestrial Planet Atmospheres With JWST

by Keith CowingNovember 1, 2023November 1, 2023

Ultra-cool dwarf stars are abundant, long-lived, and uniquely suited to enable the atmospheric study of transiting terrestrial companions with JWST. Amongst them, the most prominent is the M8.5V star TRAPPIST-1 […]

Example of forward model and retrieval applied to the case of HCN in Titan: Left: comparison between observed and best-fit simulated HCN (3-2) lines (black and red, respectively, upper panel), and the difference between the observed and fitted spectra (lower panel). Right: retrieved temperature and HCN distribution derived from the spectrum. The black and red lines, and the pink shadow show the initial and retrieved profiles, and the error bars, respectively. Figure based on Fig. 1 in Rengel et al. 2022 -- astro-ph.EP

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

Radiative Transfer and Inversion codes for Characterizing Planetary Atmospheres: An Overview

by Keith CowingNovember 1, 2023November 1, 2023

The study of planetary atmospheres is crucial for understanding the origin, evolution, and processes that shape celestial bodies like planets, moons and comets.

Despite Venus being such a scorching wasteland, the planet is often referred to as Earth’s sister because of similarities in size, mass, density and volume. Photo: NASA/JPL

Astrogeology, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Gaia - Planetary Perspectives, Habitable Zones, Press Release, Venus

Venus Had Earth-like Plate Tectonics Billions Of Tears Ago, Study Suggests

by Keith CowingOctober 27, 2023October 27, 2023

Venus, a scorching wasteland of a planet according to scientists, may have once had tectonic plate movements similar to those believed to have occurred on early Earth, a new study […]

NASA’s Curiosity Mars rover used two different cameras to create this selfie in front of Mont Mercou, a rock outcrop that stands 20 feet tall. New analysis by Penn State researchers reveals that much of the craters on Mars today could have once been habitable rivers. Credit: NASA/JPL-Caltech/MSSS.

Astrogeology, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Habitable Zones, Mars, Missions & Hardware, Press Release, Robotics/Rovers/UAVs

Curiosity Rover Finds New Evidence Of Ancient Mars Rivers, A Key Signal For Life

by Keith CowingOctober 24, 2023October 24, 2023

New analysis of data from the Curiosity rover reveals that much of the craters on Mars today could have once been habitable rivers.

Mass-radius diagram showing confirmed planets with mass uncertainties < 20% in grey circles, with TOI-544 b shown as the black circle. Left: the coloured tracks show different potential planet compositions from Zeng et al. (2019), assuming a planetary equilibrium temperature of 1000 K. The dashed lines show compositions of an Earth-like rocky core surrounded by a layer of H-He in varying percentages by mass, the solid lines show water world compositions with varying water mass fractions, the dotted lines show rocky and Earth-like rocky compositions. TOI-544 b is closest to the tracks with 100% H2O and 50% H2O with 50% rock. Right: the same as the left panel but the the dashed lines show compositions of an Earth-like rocky core surrounded by a layer of H-He in varying percentages by mass from Lopez & Fortney (2014) using the models for a 10Gyr planet, with solar metalicity and flux of 10F⊕, the solid lines show compositions from Aguichine et al. (2021) of irradiated ocean worlds with varying water mass fractions, and the dotted lines show the same rocky and Earth-like rocky compositions from Zeng et al. (2019). TOI-544 b is closest to models with either 30% water mass fraction, or a rocky core with a Hydrogen envelope of between 0.5 - 1%. The data is downloaded from the NASA Exoplanet Archive. -- astro-ph.EP

Astronomy & Telescopes, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exploration Gear & Tech, Habitable Zones, Icy Worlds, Imaging & Spectroscopy, Status Report, Water/Hycean Worlds & Oceanography

TOI-544 b: A Potential Water-world Inside The Radius Valley In A Two-planet System

by Keith CowingOctober 24, 2023October 24, 2023

We report on the precise radial velocity follow-up of TOI-544 (HD 290498), a bright K star (V=10.8), which hosts a small transiting planet recently discovered by the Transiting Exoplanet Survey […]

Atmospheric and stellar retrieval results for HAT-P-18 b. Top: Retrieved model transmission spectra from our JWST/NIRISS spectra (black errors). For each of the three retrieval codes (Poseidon; purple, SCARLET; orange, and Aurora; blue), the median retrieved spectrum (solid lines) and 1 𝜎 confidence intervals (shaded contours) are shown. The most important model features required to explain HAT-P-18 b’s NIRISS transmission spectrum are annotated. All three codes adopt the one heterogeneity model for this comparison. Bottom: Posterior probability distributions corresponding to the retrieval model in the top panel. The top row shows retrieved atmospheric properties with constrained values, the middle row shows non-detected chemical species with abundance upper limits, and the bottom row shows the retrieved unocculted starspot properties. Each histogram is annotated with the retrieved median and ± 1 𝜎 confidence intervals from the Poseidon retrieval for reference (see Table 4 for the results from all three codes). -- astro-ph.SR

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

Near-Infrared Transmission Spectroscopy of HAT-P-18b with NIRISS: Disentangling Planetary and Stellar Features in the Era of JWST

by Keith CowingOctober 24, 2023October 24, 2023

The JWST Early Release Observations (ERO) included a NIRISS/SOSS (0.6-2.8μm) transit of the ∼850K Saturn-mass exoplanet HAT-P-18b. Initial analysis of these data reported detections of water, escaping helium, and haze.

Illustration of our strategy to detect habitable exoplanetary environment via CO2 depletion. Each of the planets to the right hand side of the star describes a different scenario discussed in the text (along with illustrative atmospheric concentrations). The panel on the left hand side depicts a simulation of the transmission spectrum of the temperate terrestrial planet TRAPPIST-1 f. We explore the detectability of an atmosphere with ∼ 10 JWST/NIRSpec Prism transit observations, the minimum needed to produce a reliable diagnostic. Note that the deviation from a flat signal (no atmosphere) is primarily supported by the strong absorption features of CO2, notably at 4.3 µm (highlighted). Exo-atmospheric models from 142 were used to make that panel. On the lower right hand side, we illustrate a simplified view of a carbon cycle involving surface liquid water and biology sequestering cycle and producing a depletion in atmospheric carbon. Atmospheric concentrations given near the planets are illustrative. astro-ph.EP

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Icy Worlds, Status Report, TRAPPIST-1, Water/Hycean Worlds & Oceanography

Atmospheric Carbon Depletion As A Tracer Of Water Oceans And Biomass On Temperate Terrestrial Exoplanets

by Keith CowingOctober 24, 2023October 24, 2023

The conventional observables to identify a habitable or inhabited environment in exoplanets, such as an ocean glint or abundant atmospheric O2, will be challenging to detect with present or upcoming […]

Individual components of our 3-planet RV model of TOI-1266 and corresponding GLS periodograms. From top to bottom: the raw LBL RVs, stellar RV activity, TOI-1266 b, TOI-1266 c, the planet candidate TOI-1266 d, and the residuals. The residuals do not show any evidence for unaccounted periodicities in the GLS. The vertical shaded regions in the left column highlight each TESS sector’s observing window (annotated at the top) and reveals where we have contemporaneous TESS and spectroscopic observations. Similarly, the vertical dashed lines highlight the epochs of our ground-based transit observations of either TOI-1266 b or c, using the ARCTIC and WIRC cameras. The vertical dashed lines in the right column depict the orbital periods of the transiting TOI-1266 planets, the candidate planet d, and the stellar rotation period inferred from our 𝐻 𝛼 time series. -- astro-ph.EP

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

Masses, Revised Radii, and a Third Planet Candidate in the “Inverted” Planetary System Around TOI-1266

by Keith CowingOctober 24, 2023October 24, 2023

Is the population of close-in planets orbiting M dwarfs sculpted by thermally driven escape or is it a direct outcome of the planet formation process? A number of recent empirical […]

The pebble surface density for scenario 1 (top) and scenario 2 (bottom) is depicted for different α-viscosities, dependent on disk radius and time. In each case, the red vertical line denotes the water-ice line, and the green line marks the position of the gas giant, if present. In the scenario with a gas giant, the accumulation of blocked pebbles exterior to the gas giant’s position is visible. Further accumulations within the water-ice line result from the recondensation of outwardly diffusing gas at different evaporation lines. -- astro-ph.EP

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

Constraining The Formation History Of The HAT-P-11 System By Atmospheric Abundances

by Keith CowingOctober 23, 2023October 20, 2023

The chemical fingerprint of a planet reveals information about its formation history regarding when and where it formed. The water content of a planet can help to constrain its formation […]

Atmospheres, Climate, Weather

Ice-Exposing Impact Crater Surrounded by Polygon Terrain On Mars

A Roadmap To The Efficient And Robust Characterization Of Temperate Terrestrial Planet Atmospheres With JWST

Radiative Transfer and Inversion codes for Characterizing Planetary Atmospheres: An Overview

Venus Had Earth-like Plate Tectonics Billions Of Tears Ago, Study Suggests

Curiosity Rover Finds New Evidence Of Ancient Mars Rivers, A Key Signal For Life

TOI-544 b: A Potential Water-world Inside The Radius Valley In A Two-planet System

Near-Infrared Transmission Spectroscopy of HAT-P-18b with NIRISS: Disentangling Planetary and Stellar Features in the Era of JWST

Atmospheric Carbon Depletion As A Tracer Of Water Oceans And Biomass On Temperate Terrestrial Exoplanets

Masses, Revised Radii, and a Third Planet Candidate in the “Inverted” Planetary System Around TOI-1266

Constraining The Formation History Of The HAT-P-11 System By Atmospheric Abundances

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)