HST/WFC3 Archives

UVIS (G280) white light curves for all three observed transits. The +1 and −1 orders are fitted separated and are shown on the top and bottom rows in red and blue, respectively. The raw light curve data are shown in dark grey, with the light grey points in the +1 order being the outlier points excluded in the white light curve fits. The model fits to the data are shown as red and blue points, and their residuals are shown individually below each plot. The full phase model, along with the systematics-removed points, are shown offset above the raw data, seen as a solid line and black points, respectively. -- astro-ph.EP

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

An HST Transmission Spectrum of the Closest M-Dwarf Transiting Rocky Planet LTT 1445Ab

by Keith CowingOctober 18, 2024October 18, 2024

Which rocky exoplanets have atmospheres, and which do not? This presumably simply question is the first that must be answered in the pathway toward understanding the prevalence of nearby habitable […]

Top panels: Results from the white light curve fit of the supreme-SPOON reduction for Visits 1 (left) and 2 (right), and fitted systematics models. The order 1 systematics-corrected light-curves are shown (teal points), binned for visual purposes, along with the best-fit transit model (black) and the systematics model including the GP component (red, with the GP scaled for visualization purposes). The vertical blue shaded regions indicate the three candidate flares with the highest signal-to-noise spectra and following typical flare evolution profiles (see Section C). Bottom panels: Spectroscopic light-curve fits to the two NIRISS/SOSS transits of GJ 9827 d from the supreme-SPOON reduction. The left panel corresponds to the first visit and the right panel to the second visit. We show the detrended broadband light-curve for order 2, and seven spectroscopic light-curves from order 1, from top to bottom. The best-fit astrophysical model is shown for each light-curve (black) and light-curves are offset relative to each other for clarity. -- astro-ph.EP

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

JWST/NIRISS Reveals The Water-rich Steam World Atmosphere of GJ 9827 d

by Keith CowingOctober 7, 2024October 7, 2024

With sizable volatile envelopes but smaller radii than the solar system ice giants, sub-Neptunes have been revealed as one of the most common types of planet in the galaxy.

Opacities as a function of wavelength for the opacity sources in the current study, computed at a temperature of 1000 K and a pressure of 0.01 bar. The opacities are weighted by their mass mixing ratios corresponding to the best-fit model from the non-isothermal + non-grey cloud retrieval on the NIRISS data. They are shown over the wavelength range covered by the three instruments in this study – NIRISS, WFC3 and STIS. -- astro-ph.EP

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

JWST/NIRISS and HST: Exploring The Improved Ability to Characterise Exoplanet Atmospheres In The JWST Era

by Keith CowingSeptember 26, 2024September 26, 2024

The Hubble Space Telescope has been a pioneering instrument for studying the atmospheres of exoplanets, specifically its WFC3 and STIS instruments. With the launch of JWST, we are able to […]

Interpretation of WASP-107b’s transmission spectrum. The observed transmission spectrum of the planet with 1σ error bars is compared to the best-fit one-dimensional radiative-convective-photochemical equilibrium models (1D-RCPE model, χ 2/Ndata=1.4) shown at a spectral resolution of R=300. The colored shaded regions show the contributions from individual gases to the best fit model. The gray dashed line shows the clear atmosphere component of the model, that is, the gas contributions without the presence of clouds or hazes. Panel a shows the broad wavelength spectrum (0.8–12 µm) of the planet. Panel b shows the fit residuals with the corresponding 2σ data error envelope. Panel c shows the NIRCam observations, while d shows HST WFC3 spectra and e shows JWST MIRI observations. The HST/WFC3 data are binned at a constant ∆λ = 0.025 µm, the NIRCam data are binned at ∆λ = 0.015 µm, and the MIRI data are binned at ∆λ = 0.15025 µm. astro-ph.EP

Astrochemistry, Astrogeology, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

A High Internal Heat Flux and Large Core in a Warm Neptune Exoplanet

by Keith CowingMay 22, 2024May 22, 2024

Interactions between exoplanetary atmospheres and internal properties have long been hypothesized to be drivers of the inflation mechanisms of gaseous planets and apparent atmospheric chemical disequilibrium conditions.

Astrochemistry, Astronomy & Telescopes, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Gas Giants, Imaging & Spectroscopy, Press Release

Webb Studies Inflated Exoplanet WASP-107 b

by Keith CowingMay 20, 2024May 20, 2024

Why is the warm gas-giant exoplanet WASP-107 b so puffy? Two independent teams of researchers have an answer.

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.

Voyager 2/ISS images of Uranus and Neptune released shortly after the Voyager 2 flybys in 1986 and 1989, respectively, compared with a reprocessing of the individual filter images in this study to determine the best estimate of the true colours of these planets. CREDIT Patrick Irwin.

Astronomy & Telescopes, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Ice Giant, Icy Worlds, Imaging & Spectroscopy, Mapping, Geodesy, Cartography, Bathymetry, Neptune, Press Release, Uranus

Calibrating Instruments For Exoplanets: What Neptune And Uranus Really Look Like

by Keith CowingJanuary 6, 2024May 12, 2025

Neptune is fondly known for being a rich blue and Uranus green – but a new study has revealed that the two ice giants are actually far closer in colour […]

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.

HST/WFC3

An HST Transmission Spectrum of the Closest M-Dwarf Transiting Rocky Planet LTT 1445Ab

JWST/NIRISS Reveals The Water-rich Steam World Atmosphere of GJ 9827 d

JWST/NIRISS and HST: Exploring The Improved Ability to Characterise Exoplanet Atmospheres In The JWST Era

A High Internal Heat Flux and Large Core in a Warm Neptune Exoplanet

Webb Studies Inflated Exoplanet WASP-107 b

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

Calibrating Instruments For Exoplanets: What Neptune And Uranus Really Look Like

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

Tricorder Tech: New Handheld Device Maps Chemical Composition Using Infrared Light

No Statistically Significant Evidence For A Correlation Between Stellar And planetary Composition

Water Planet Recon: How Accurately Can We Measure Earth Ocean’s Deepest Point?

Webb Reveals A Stunning Panorama Of Star Formation

Deep Learning of SHERLOC Raman Spectra For Facilitating Mars Astromaterial Identification