WASP-17 b Archives - Astrobiology

Particle temperature normalized by the gas temperature as a function of pressure and particle radius for SiO2, Mg2SiO4, Fe, and Al2O3. The hatched region denotes the phase space where the particle temperature exceeds the condensation temperature, leading to the sublimation of clouds. -- astro-ph.EP

Exoplanets, -moons, -comets

Radiatively Controlled Thermal Stability of High-Altitude Clouds in Exoplanetary Atmospheres

by Keith CowingJune 27, 2026June 27, 2026

[astro-ph.EP] One of the most striking findings of exoplanetary science is the ubiquity of clouds. A conventional approach to infer the cloud compositions is to utilize the thermochemical equilibrium model […]

Artistic representation of WASP-94 A b. Clouds build as air flows over the dark side of the planet, reaching a large swell by daybreak. The clouds dissipate on the dayside, leaving clear skies in the early evening. Image courtesy of Hannah Robbins/Johns Hopkins University

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Gas Giants, Imaging & Spectroscopy, Status Report, Water/Hycean Worlds & Oceanography

Astronomers Observe Exoplanet Atmospheres With New Cloud-detecting Method

by Keith CowingMay 22, 2026May 22, 2026

Every morning, clouds roll in, and by evening, they have cleared off. This sounds like a weather forecast for a coastal city here on Earth — but it’s for WASP-94A […]

Mg/Si ratios of JWST-observed hot Jupiter host stars versus separation (semi-major axis).

Astrogeology, Astronomy & Telescopes, Atmospheres, Climate, Weather, Brown Dwarfs, Imaging & Spectroscopy, Status Report

Bridging the Gap: Using Brown Dwarfs to Examine Silicate Clouds in Giant Exoplanet Atmospheres

by Keith CowingMarch 17, 2026March 17, 2026

We present results from examining the silicate cloud modeling of four JWST-observed hot Jupiters in the context of brown dwarf theory to further explore signatures of formation in present-day atmospheres.

Comparison of nested POSEIDON Model B retrievals with and without H− and AlO, zooming on the 0.2 to 1.05 µm region. We display median retrieved spectra (solid lines) and 1σ confidence regions (shaded regions). Model B with both H− and AlO (blue) is the best fit model, but only due to imparting fine structure to fit the STIS slope. Future observations of the 0.2-0.8 µm region will provide more reliable inferences of metal species. -- astro-ph.EP

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

JWST-TST DREAMS: A Precise Water Abundance for Hot Jupiter WASP-17b from the NIRISS SOSS Transmission Spectrum

by Keith CowingDecember 11, 2024December 11, 2024

Water has proven to be ubiquitously detected in near-infrared (NIR) transmission spectroscopy observations of hot Jupiter atmospheres, including WASP-17b.

The combined STIS G430L and G750L spectrum of WASP-39 b (top left), WASP-121 b (top right), WASP-69 b (bottom left), and WASP-17 b (bottom right). Each color (common between planets) corresponds to a different systematics detrending technique, either using linear or GP methods and either between 1-10 PCs or the 10 initial input vectors. -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report, Stellar Cartography

HST SHEL: Enabling Comparative Exoplanetology with HST/STIS

by Keith CowingJune 3, 2024

The Hubble Space Telescope (HST) has been our most prolific tool to study exoplanet atmospheres. As the age of JWST begins, there is a wealth of HST archival data that […]

The Bayes Factor resulting from the difference between the ln(E) of the stellar activity model minus that of the base model, divided by Case number. For an explanation of the data sets considered in each Case, we refer the reader to Table 1. The coloured thresholds indicate the strength of the evidence, with negative values favouring the base model over the contamination model. Multiple solutions might be found by the retrieval in certain scenarios, however here we present either the solution with the highest Bayesian evidence if both models appear physically motivated, or the most physically motivated of the two solutions. -- astro-ph.EP

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

A Population Analysis of 20 Exoplanets Observed from the Optical of the Near-infrared Wavelengths with HST: Evidence for Widespread Stellar Contamination

by Keith CowingApril 26, 2024April 26, 2024

We present a population study of 20 exoplanets, ranging from Neptune-like to inflated hot-Jupiter planets, observed during transit with the STIS and WFC3 instruments aboard the Hubble Space Telescope.

The atmosphere of the hot gas giant planet WASP-17 b, depicted in this artist’s concept

Astrogeology, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Press Release

Webb Detects Tiny Quartz Crystals in Clouds of Hot Gas Giant WASP-17 b

by Keith CowingNovember 4, 2023November 4, 2023

The atmosphere of the hot gas giant planet WASP-17 b, depicted in this artist’s concept, is composed primarily of hydrogen and helium, along with small amounts of water vapor and […]