JWST Archives

Best-fitting spectrum and atmospheric properties of WD 1856 b. a. Spectral decomposition illustrating the model components required to explain WD 1856 b’s JWST transmission spectrum (FIREFLy reduction; orange circles with 1 σ error bars). The best-fitting model (black curve) contains absorption from multiple CH4 features (purple shading), H2 + He continuum absorption (dark grey shading), and tentative evidence of C2H6 near 3.4 µm (brown shading) and PH3 near 4.3 µm (orange shading). Aerosol continuum opacity (silver shading) blocks thermal emission from the deep atmosphere in windows between CH4 bands, obscuring the ‘negative spikes’ that would otherwise be observed near 0.7 µm, 2.9 µm, and longwards of 4.0 µm for a clear atmosphere. The best-fitting model without nightside thermal emission (blue dashed curve) cannot explain the significantly lower transit depths longwards of 3.5 µm. b. Retrieved atmospheric properties, planetary mass, and aerosol properties from WD 1856 b’s JWST transmission spectrum for the FIREFLy (orange histograms) and Juniper (green histograms) data reductions. The median (solid line) and 1 σ credible intervals for each parameter (dashed lines) are overlaid. c. Residuals between the data and best-fitting model. -- [astro-ph.EP]

Aerosols And Hydrocarbons In The Atmosphere Of A White Dwarf Planet

by Keith CowingJuly 12, 2026July 12, 2026

[astro-ph.EP] Most stars, including our Sun, will one day evolve into red giants and, subsequently, white dwarfs. Several planet candidates have recently been identified orbiting white dwarfs, demonstrating that planets […]

Geometry of the LTT 3780 planetary system at the time of our radio technosignature observations. The left panel shows the sky-plane (X–Y) view as seen from Earth, while the right panel shows the top-down (X–Z) view of the system. The orbits of planets b (blue) and c (green) are shown relative to the host star (yellow). Our observations from the ATA, mentioned in Table 1 on 5th November 2025, were timed to coincide with a planet–planet occultation (PPO), when planet b passes behind planet c along the line of sight, providing a unique configuration to search for radio technosignatures during mutual planetary alignment.-- [astro-ph.IM]

SETI & Technosignatures

A Search For Narrowband Technosignatures From LTT 3780 With The Allen Telescope Array And The Karl G. Jansky Very Large Array

by Keith CowingJuly 9, 2026July 9, 2026

[astro-ph.IM] The LTT3780 system hosts two known exoplanets-LTT3780b, a rocky super-Earth, and LTT3780c, a temperate sub-Neptune-orbiting a nearby M dwarf on opposite sides of the radius valley. LTT3780c has been […]

Artist’s concept of a bare rocky planet orbiting a red dwarf star. Artwork: NASA, ESA, CSA, Dani Player (STScI) larger image

Exoplanets, -moons, -comets

First Completed Rocky Worlds Program Observations Open New Era in Exoplanet Studies

by Keith CowingJuly 9, 2026July 9, 2026

[STScI] Scientists leading the astronomy community’s most ambitious effort to study rocky planets outside of our solar system have reached a major milestone.

The mid-infrared transmission spectrum of TOI-270 d obtained with the JWST MIRI LRS instrument and the JExoRES pipeline. The data points with error bars (in dark red) show the observed spectrum. The horizontal error bars correspond to the spectral bin width. The dark blue curve denotes the median retrieved spectral fit to this MIRI dataset using the canonical retrieval discussed in Section 3.2, while the two lighter shaded regions denote the 1σ and 2σ intervals. The yellow points denote the binned median model. -- astro-ph.EP

Exoplanets, -moons, -comets

The Mid-Infrared Transmission Spectrum of the Temperate Sub-Neptune TOI-270 d

by Keith CowingJuly 8, 2026July 7, 2026

[astro-ph.EP] Observations of temperate sub-Neptunes with JWST have ushered in a new era for atmospheric characterization of small exoplanets.

Carbon ion chemistry network. The red arrows indicate endoergic reactions, which proceed rapidly at high T or in regions with significant FUV-pumped H∗ 2 . We also show possible reactions (dashed) involving Polyaromatic Hydrocarbon (PAH) and Hydrogenated Amorphous Carbon (HAC) grains, which may be relevant in certain conditions. The figure is adapted from Goicoechea et al. (2025a). -- astro-ph.GA

Astrochemistry

Searching For The Elusive CH2+ With The James Webb Space Telescope. Another Carbocation To Constrain Astrochemical Networks

by Keith CowingJuly 7, 2026July 7, 2026

[astro-ph.GA] Carbocations are key species in interstellar chemistry, providing entry points for building larger hydrocarbons. CH+, and more recently, CH3+, have been detected. Other carbocations await detection to provide a […]

Exoplanets, -moons, -comets

Photochemical Production of CS2 in Temperate-to-Warm Gas Giant Exoplanet Atmospheres

by Keith CowingJuly 7, 2026July 7, 2026

[astro-ph.EP] Sulfur chemistry has emerged as an important probe of exoplanet atmospheres in the JWST era, although observational constraints have thus far been largely limited to SO2 and H2S in […]

Integrated MIRI-MRS spectrum of HK Tau A (top) and B (bottom) in grey, with the black line representing the continuum baseline. In the top panel, the insets zoom into wavelength regions where molecular emission from 12CO, H2O, 12CO2 , and H2 is visible. In the bottom panel, the shaded bands in the indicate the main ices absorption regions. H2 rotational lines are marked with blue ticks, and gas emission features are labelled where present. -- astro-ph.EP

Astrochemistry

MINDS: Complementary Inclinations In The Binary Ssystem HK Tau Reveal Gas- And Ice-phase Chemistry

by Keith CowingJuly 7, 2026July 7, 2026

[astro-ph.EP] HK Tau is a roughly equal mass pre-main sequence binary system consisting of a low-inclination primary (57 deg) and an edge-on (83 deg) secondary. We present JWST/MIRI observations targeting […]

The transmission spectrum of TOI-1231 b. The observed JWST spectrum and retrieved model fits are shown for the fiducial retrieval using the JexoPipe data, considering the six prominent CNO molecules, with a single offset and no stellar heterogeneity, as discussed in Section 3. For visual clarity, the data shown here have been binned to R∼50. A retrieved offset of 79.38 ppm has been added to the NIRSpec data. The dark blue line indicates the median retrieved spectrum, with the shaded regions indicating the 1σ and 2σ uncertainties. The yellow points show the median retrieved spectrum binned at the same resolution as the plotted data. -- astro-ph.EP

Exoplanets, -moons, -comets

Transmission Spectrum of the Benchmark Temperate Exo-Neptune TOI-1231 b

by Keith CowingJuly 7, 2026July 7, 2026

[astro-ph.EP] The JWST is revolutionizing our understanding of the temperate sub-Neptune population through atmospheric spectroscopy.

Artist concept of the gas giant planet WD1856b orbiting a white dwarf star. The planet is 7 times larger than the Earth-sized white dwarf it orbits. WD1856b has methane and hazes in its atmosphere, which would give it a similar colour to Saturn's moon Titan. The white dwarf formed from a star that died 5 billion years ago and has been cooling ever since, giving it an orange colour similar to the sun. Credit NASA, ESA, CSA, Ralf Crawford (STScI)

Exoplanets, -moons, -comets

How A Giant Planet Survived Its Star’s Death

by Keith CowingJuly 4, 2026July 4, 2026

[Northwestern University] When astronomers discovered a giant planet orbiting a dead star in 2020, they wondered how it survived its star’s violent demise. Now, observations from NASA’s James Webb Space […]

Left panel: Sketch of the V883 Ori outbursting protostar: the luminosity increase of the central source pushes the snowline outwards (from 80 au in the midplane to 160 au in the disk surface layers), releasing iCOMs in gas-phase at dust temperatures > 100 K. However, the dust continuum optical depth in the inner 40 au screens the emission from complex organics despite their expected high column densities after sublimation (adapted from Lee et al., 2019b). Right panel; ALMA observations towards V883 Ori shows a ring of CH3OH emission, because methanol is observed in the region where 𝑇 > 100 K (i.e. inside the snowline) and where the dust optical depth becomes lower than 1, as shown in the sketch. The lower frequencies covered by the SKAO will allow us to probe iCOMS emission in the innermost 40 au region of these disks thanks to the low dust optical depths at cm wavelengths (adapted from Tobin et al., 2023). -- astro-ph.SR

Astrochemistry

Unveiling Complex Chemistry In Planet-forming Disks With The SKAO

by Keith CowingJuly 4, 2026July 4, 2026

[astro-ph.SR] The chemical composition of planets is inherited from that of the natal protoplanetary disk at the time of planet formation.

JWST

Aerosols And Hydrocarbons In The Atmosphere Of A White Dwarf Planet

A Search For Narrowband Technosignatures From LTT 3780 With The Allen Telescope Array And The Karl G. Jansky Very Large Array

First Completed Rocky Worlds Program Observations Open New Era in Exoplanet Studies

The Mid-Infrared Transmission Spectrum of the Temperate Sub-Neptune TOI-270 d

Searching For The Elusive CH2+ With The James Webb Space Telescope. Another Carbocation To Constrain Astrochemical Networks

Photochemical Production of CS2 in Temperate-to-Warm Gas Giant Exoplanet Atmospheres

MINDS: Complementary Inclinations In The Binary Ssystem HK Tau Reveal Gas- And Ice-phase Chemistry

Transmission Spectrum of the Benchmark Temperate Exo-Neptune TOI-1231 b

How A Giant Planet Survived Its Star’s Death

Unveiling Complex Chemistry In Planet-forming Disks With The SKAO

On The Foundations Of Anthropic Reasoning: Implications For Life Across The Universe

NASA Curation Community Conversation Webinar

The Atmospheric Chemistry and Surface Interactions on Mars (ACSIOM) Workshop 2025

An ALMA View On Molecular Complexity: Water, Methanol, And Methyl Formate In The HD 100546 And IRS 48 Disks

The Occurrence of Circumbinary Planets Around TESS M-dwarf Eclipsing Binaries