MIRI Archives

Planets that will be observed with MIRI in transit, in JWST Cycles 1-5. As mentioned in section 5, we see a wide variety of planet sizes and equilibrium temperatures. The currently published planets are shown in black dots, and listed in Table 1 and Figure 1. We have ommitted the white dwarf planet WD 1856 b (Teq = 160K, Rp = 10.2R⊕, cycle 4), as well as the disintergrating planets K2-22 b (see section 2.1) and BD+05 4868 A b (Teq = 1820K, unknown Rp, cycle 4). -- [astro-ph.EP]

A Homogeneous Survey Of JWST MIRI Transmission Spectra Of 10 Exoplanets

by Keith CowingSeptember 7, 2026September 7, 2026

[astro-ph.EP] The launch of JWST has enabled unprecedented atmospheric characterization of exoplanets. In particular, the JWST-MIRI instrument in the mid-infrared enables probing of molecular species that are harder to detect […]

This image showcases the location of the highly evolved star IRS 3, which is located just 0.55 light-years from Sagittarius A*, the Milky Way galaxy's central supermassive black hole. The data in this image were taken with Webb programmes #1939 (J. Lu), #3571 (F. Yusef-Zadeh), #2491 (N. B. Sabha), and #2075 (C. Chan). Credit: ESA/Webb, NASA & CSA, F. Peißker, J. Lu, F. Yusef-Zadeh, N. B. Sabha, C. Chan Larger image

Astrochemistry

Dust And Water Found Around The Milky Way’s Central Black Hole

by Keith CowingAugust 17, 2026August 17, 2026

[ESA] The new observations provide the most detailed mid-infrared view yet of the highly evolved star IRS 3, which is located just 0.55 light-years from Sagittarius A*, the Milky Way […]

Mid-infrared image of the IRS 3 environment, observed with NACO (VLT) and MIRI/MRS (JWST). The background image is in the L band (3.6 μm), the yellow inset shows a slice from the channel 3 long data cube covering 15.41−17.98 μm. The light blue boxes highlight an area of 1.6″ × 1.6″. A yellow × marks the SMBH Sgr A*, located at RA 17h45m40.05s and Dec −29:00:28.120. The projected distance between Sgr A* and IRS 3 is about 4.4 arcsec, corresponding to 0.17 parsec. The NACO field of view (FOV) is about 13.5″ × 6.5″. In both the NACO and MIRI MRS images, the emission from IRS 3 is dominated by the extended envelope of the AGB star. -- University of Cologne

Astrochemistry

A Stellar Envelope Near The Black Hole Sgr A* Contains Water

by Keith CowingAugust 12, 2026August 12, 2026

[University of Cologne] Studies of the star IRS 3, located near the black hole at the centre of our galaxy, suggest that the star is emitting large quantities of gas […]

This image features data from Webb’s NIRCam

Astrochemistry

Astrochemistry: Dust And Water Spotted Close To A Giant Black Hole

by Keith CowingAugust 11, 2026August 11, 2026

[ESA]. Using the NASA/ESA/CSA James Webb Space Telescope, an international team of astronomers have discovered that dust and water can form and survive surprisingly close to the supermassive black hole […]

Vertical cut through the best-fit disk model on a logarithmic radial scale. Shown are temperatures, where the gas density, ϱdisk, exceeds an assumed ISM density of ϱISM = 2.7 × 10−24 g cm−3 (Ferrière 2001) by a factor of 1000. The snowline at Tsnow = 170 K and the 100 K-line, as well as the unity optical depth lines at a wavelength of 3.1 µm (computed for the best-fit model described in Sect. 5.2.2) measured from the star to the observer and from observer to the star, illustrate the temperature and dust density structure of the disk. -- [astro-ph.EP]

Astrochemistry

Spatial Distribution Of Water Ice In The Protoplanetary Silhouette Disk d216-0939

by Keith CowingAugust 7, 2026August 7, 2026

[astro-ph.EP] The composition of rocky planets depends on the dust in their natal protoplanetary disk (PPD), potentially containing water ice. Crystalline water ice was detected in the PPD d216-0939 in […]

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.

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 […]

Continuum-subtracted emissivity of 3I/ATLAS in the 6-7 µm region in black, compared to a set of reference spectra which are described in the main text.

Comets and Asteroids

The Dust Mineralogy of Interstellar Comet 3I/ATLAS from JWST/MIRI Observations

by Keith CowingJuly 3, 2026July 3, 2026

[astro-ph.EP] We present the first spectroscopic mineralogical analysis of the dust coma of an interstellar object (ISO) from JWST mid-infrared spectroscopy of 3I/ATLAS (3I).

NIRSpec average spectrum of Titan (black) compared with a radiative transfer calculation in which the surface albedo decreases smoothly with wavelength beyond 4.9 µm (red). The blue line shows the difference between the observed and synthetic spectra, shifted by 0.005 for clarity. The 5.11-µm absorption is clearly missing in the model. The small mismatch below 4.93 µm is due to a component of the non-LTE CO emission not included in the model. -- astro-ph.EP

Astrochemistry, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Icy Worlds, Imaging & Spectroscopy, Pluto, Status Report, Titan

An Unidentified Absorption Feature At 5.11 μm On The Surface Of Titan And Pluto From JWST Spectroscopy

by Keith CowingJune 12, 2026June 12, 2026

Titan possesses a thick N2-CH4 atmosphere that makes it difficult to study its surface spectroscopically. The chemical composition of the solid surface of Titan thus remains very uncertain.

Top: coma maps of H2O, CO2, and CH4, computed as the molecular column density from a pixel-by-pixel retrieval analysis for Observations 6, 15, and 6, respectively. The sunward and target velocity directions are denoted by the white arrows. The target centroids, computed as the photocenter in the median-stacked images (Figure 1), are marked with the black points. For H2O and CO2, the white contours correspond to emission levels of 50% and 20% relative to the maximum value and illustrate the slight antisunward extension of the respective comae. The contours are omitted in the CH4 panel, due to the poorer signal-to-noise ratio of the data. Bottom: corresponding median-stacked images across the continuum wavelengths within each fluorescence region. The H2O coma map shows a significant enhancement in the emission level at large nucleocentric distances relative to the dust continuum, indicating extended H2O production within the coma. -- The Astrophysical Journal Letters

Astrochemistry, Astronomy & Telescopes, Biogeochemical Cycles & Geobiology, Biophysics, Biosignatures & Paleobiology, Comets and Asteroids, Icy Worlds, Imaging & Spectroscopy, Interstellar, Press Release

Webb Detects Methane on Interstellar Comet 3I/ATLAS

by Keith CowingJune 2, 2026June 2, 2026

NASA’s James Webb Space Telescope has collected its first mid-infrared chemical fingerprint of an interstellar object during a recent revisit to comet 3I/ATLAS. The team’s results published recently in The […]

MIRI

A Homogeneous Survey Of JWST MIRI Transmission Spectra Of 10 Exoplanets

Dust And Water Found Around The Milky Way’s Central Black Hole

A Stellar Envelope Near The Black Hole Sgr A* Contains Water

Astrochemistry: Dust And Water Spotted Close To A Giant Black Hole

Spatial Distribution Of Water Ice In The Protoplanetary Silhouette Disk d216-0939

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

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

The Dust Mineralogy of Interstellar Comet 3I/ATLAS from JWST/MIRI Observations

An Unidentified Absorption Feature At 5.11 μm On The Surface Of Titan And Pluto From JWST Spectroscopy

Webb Detects Methane on Interstellar Comet 3I/ATLAS

Chemical Diversity Of Dense Cores In Orion B: The Role Of The Environment

Precise C-N-O Abundances of Individual Galaxies In The First Billion Years From Ultra-Deep, Rest-UV-to-Optical JWST Spectroscopy

Bacteriophage Qβ: Six Decades at the Frontier of Molecular and Viral Evolution Genome, Particle And Mutational Landscape Of Bacteriophage Qβ

Secondary Ion-Ice Chemistry in UV-Irradiated Oxygen Ice: New Astrochemical Models Including Bulk Ionic Species

Controlled Near-space Exposure Induces Community Restructuring In An Ocean Water Microbiome