Transmission spectroscopy Archives

Airmass variation and S/N of an ESPRESSO spectral order covering wavelengths from 567.76 nm to 576.42 nm, chosen as a midpoint in the selected Fe i spectral lines, as a function of the orbital phase of HD 189733 b. Blue points correspond to observations from 11 August 2021, and red points to those from 31 August 2021. The darker shaded region marks the phases where the planet is fully in transit, with lighter shading indicating the ingress and egress phases. -- astro-ph.SR

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

Exploring The Surface Of HD 189733 via Doppler Shadow Analysis Of Planetary Transits

by Keith CowingMarch 20, 2026March 20, 2026

Transmission spectroscopy has greatly advanced the study of exoplanet atmospheres, but stellar surface heterogeneities can contaminate transit spectra. Characterising how stellar spectra vary across the stellar disc is therefore essential […]

Schematic representation of the effect of stellar contamination (TLS) with actual examples of the effect of TLS in simulated signals.

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

Efficient Reduction Of Stellar Contamination And Noise In Planetary Transmission Spectra Using Neural Networks

by Keith CowingFebruary 27, 2026February 27, 2026

Context: JWST has enabled transmission spectroscopy at unprecedented precision, but stellar heterogeneities (spots and faculae) remain a dominant contamination source that can bias atmospheric retrievals if uncorrected.

SEDs scaled to the EEID (top panel) and to the semi-major axis of each planet b (bottom panel). In the bottom panel the wavelength range is changed to expand the X-ray and ultraviolet range. The Sun at 1 au is overplotted in black for reference in both panels. Dashed lines show regions where proxies were used. -- astro-ph.EP

Astronomy & Telescopes, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Press Release, Stellar Cartography

The MUSCLES Extension for Atmospheric Transmission Spectroscopy: Spectral energy distributions For 20 Exoplanet Host Stars That JWST Observed in Cycle 1

by Keith CowingJanuary 9, 2026January 9, 2026

Correctly interpreting JWST spectra of close-in exoplanets requires a measurement of the X-ray and ultraviolet light that the planets receive from their host stars. Here we provide spectral energy distributions […]

The atmospheric compositions ruled out by the Tiberius dataset binned at 60 pixels.

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

JWST COMPASS: A NIRSpec G395H Transmission Spectrum Of The Super-Earth GJ 357 b

by Keith CowingJuly 12, 2025July 12, 2025

We present JWST NIRSpec/G395H transmission spectroscopy observations of GJ 357 b, a warm (Teq≈525 K) super-Earth (1.2 R⊕, 1.84 M⊕) orbiting a nearby M3-type star, with a median precision of […]

Graphical Abstract -- Earth, Planets and Space via X-mol

Astrochemistry, Astrogeology, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Imaging & Spectroscopy, Interstellar, Status Report

Exploring The Formation And Alteration Of Organics In Ice: Experimental Insights For Astrochemistry And Space Missions

by Keith CowingMay 30, 2025May 26, 2025

The formation and alteration of organic molecules within the Solar System and beyond is closely related to the life cycle of ice in space. Cold molecular clouds in the interstellar […]

Diagram of TOI-5800 system. The star is shown to scale with the planet’s orbit. -- astro-ph.EP

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

An Eccentric Sub-Neptune Moving Into the Evaporation Desert

by Keith CowingMay 16, 2025May 16, 2025

Though missions such as Kepler, K2, and TESS have discovered >2,000 sub-Neptune and Neptunian planets, there is a dearth of such planets at close-in (P≲3 days) orbits.

Period-radius injection-recovery map for TOI 2076. Blue points indicate recovered signals, while red points mark signals that were not recovered. Only 20% of injected planets are shown for clarity. The background is color-coded by the overall completeness in a given bin. The previously known planets in the system are marked as the gold stars, TOI 2076 e is marked as the green star, and candidate TOI 2076 f is marked as the gray circle. -- astro-ph.EP

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

TESS Investigation -Demographics of Young Exoplanets (TI-DYE) III: An Inner Super-Earth In TOI-2076

by Keith CowingMay 13, 2025

Young (<500 Myr) multi-planet transiting systems are valuable environments for understanding planet evolution by offering an opportunity to make direct comparisons between planets from the same formation conditions.

A visual comparison of transmission spectra measured for various planets during transit (red points) and out-oftransit (black points). The p-value of an Anderson-Darling test comparing the two measurements is shown it the title of each sub-figure. The out-of-transit measurements were generated via 1000 bootstrap simulations where the white-light transit signal (see Table 3) was injected at various times of mid-transit and measured the same way as the in-transit data. The top row of planets have a calculated p-value of p < 0.05 indicating the in-transit and out-of-transit data are statistically different from one another. The bottom row of planets have p-values of p > 0.05 indicating they are not statistically dis-similar to the boot-strap simulations. For these planets we additionally compared previous measurements from the Exoplanet Archive with a flat-line using an R 2 metric. We find the previous measurements all have an R 2 < 0.54 which suggests the atmospheric signal is likely consistent with a flat line and the consistency between in-transit and out-of-transit observations may be because the spectra is naturally featureless. -- astro-ph.EP

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

Ground-Based Reconnaissance Observations Of 21 Exoplanet Atmospheres With The Exoplanet Transmission Spectroscopy Imager

by Keith CowingMarch 17, 2025September 18, 2025

One of the most prolific methods of studying exoplanet atmospheres is transmission spectroscopy, which measures the difference between the depth of an exoplanet’s transit signal at various wavelengths and attempts […]

Patterns of atmospheric asymmetry and their different impacts on light curves. The blue solid lines and grey dashed lines in the figures on the right of each panel correspond to the light curves of the blue and grey disks of the planet’s shadow in the schematics on the left, respectively. (a) A displacement of the planet’s shadow along the X–axis (morning-evening asymmetry) causes a shift of the central transit time t0. (b) A displacement along the Y –axis (north-south asymmetry) causes a change in the transit duration. (c) Opposite displacements along the X–axis between ingress and egress also alter the transit duration. (d) Changes in the apparent radius result in variations in both the transit depth and duration. In Panel (d), the radius of the blue disk is exaggerated by a factor of 5 compared to the disk producing the blue light curve, to highlight the differences between the grey and blue disks. -- astro-ph.EP

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

Probing 2D Asymmetries Of An Exoplanet Atmosphere From Chromatic Transit Variation

by Keith CowingMarch 17, 2025September 18, 2025

We propose a new method for investigating atmospheric inhomogeneities in exoplanets through transmission spectroscopy. Our approach links chromatic variations in conventional transit model parameters (central transit time, total and full […]

Planet mass versus equilibrium temperature with each point color-coded representing their CO2-L index value. The background color gradients are model predictions from the PLATON generic grid under Solar System mass-metallicity trend or uniform metallicity assumptions. -- astro-ph.EP

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

Statistical Trends In JWST Transiting Exoplanet Atmospheres

by Keith CowingJanuary 10, 2025January 10, 2025

Our brains are hardwired for pattern recognition as correlations are useful for predicting and understanding nature. As more exoplanet atmospheres are being characterized with JWST, we are starting to unveil […]

Transmission spectroscopy

Exploring The Surface Of HD 189733 via Doppler Shadow Analysis Of Planetary Transits

Efficient Reduction Of Stellar Contamination And Noise In Planetary Transmission Spectra Using Neural Networks

The MUSCLES Extension for Atmospheric Transmission Spectroscopy: Spectral energy distributions For 20 Exoplanet Host Stars That JWST Observed in Cycle 1

JWST COMPASS: A NIRSpec G395H Transmission Spectrum Of The Super-Earth GJ 357 b

Exploring The Formation And Alteration Of Organics In Ice: Experimental Insights For Astrochemistry And Space Missions

An Eccentric Sub-Neptune Moving Into the Evaporation Desert

TESS Investigation -Demographics of Young Exoplanets (TI-DYE) III: An Inner Super-Earth In TOI-2076

Ground-Based Reconnaissance Observations Of 21 Exoplanet Atmospheres With The Exoplanet Transmission Spectroscopy Imager

Probing 2D Asymmetries Of An Exoplanet Atmosphere From Chromatic Transit Variation

Statistical Trends In JWST Transiting Exoplanet Atmospheres

Curiosity Mars Rover Discovers A Field Of Honeycomb Textures

Viking Science

Constraining The Lives And Times Of Exoplanets Through Evolutionary Bayesian Retrievals

Project Hephaistos — III. Characterizing Anomalous Infrared Sources Identified As Dyson-sphere Candidates

SCoRE: The Surface Composition Of Rocky Exoplanets