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Many rocky planets formed with large, H2-rich atmospheres. Here, the authors show that the loss of these primary atmospheres from temperate planets such as TRAPPIST-1e typically leaves behind secondary atmospheres and habitable surface conditions.

Time-series observations from the JWST of the transiting exoplanet WASP-39b show gaseous water in the planet’s atmosphere and place an upper limit on the abundance of methane.

The transmission spectrum of the exoplanet WASP-39b is obtained using observations from the Single-Object Slitless Spectroscopy mode of the Near Infrared Imager and Slitless Spectrograph instrument aboard the JWST.

Two double-sun exoplanets have been discovered by the Kepler spacecraft, establishing a new class of ‘circumbinary’ exoplanets and suggesting that at least several million such systems exist in our Galaxy.

The dayside thermal emission spectrum and brightness temperature map of the ultra-hot Jupiter WASP-18b obtained from the NIRISS instrument on the JWST showed water emission features, an atmosphere consistent with solar metallicity, as well as a steep and symmetrical decrease in temperature towards the nightside.

Heart contraction, which is decreased in disease, is determined by Ca²⁺binding to troponin C. Here, the authors combine a protein engineering approach with gene therapy to modulate heart contractility in mice with the use of rationally designed Troponin C variants, suggesting a new therapy for diseased hearts.

WASP-12b is a planet of 1.4 Jupiter masses that orbits at a mean distance of only 3.1 stellar radii from its star; its orbital period is 1.1 days, and its radius (1.79 times that of Jupiter) is unexpectedly large. An analysis of its properties now reveals that the planet is losing mass to its host star at a rate of ∼10⁻⁷ Jupiter masses per year, and that dissipation of the star's tidal perturbation in the planet's convective envelope provides the energy source for its large volume.

V1298 Tau b is a 20–30-Myr-old Jovian-sized planet with a haze-free, metal-poor atmosphere and a potentially hot interior. These properties suggest that V1298 Tau b formed in situ via pebble accretion and that it is still evolving and likely to become a Neptune- or sub-Neptune-sized planet.

Stellar data from the Kepler spacecraft are used to infer the existence of a sub-Mercury-sized exoplanet, the smallest yet discovered, in orbit around a Sun-like star.

The medium-resolution transmission spectrum of the exoplanet WASP-39b, described using observations from the Near Infrared Spectrograph G395H grating aboard JWST, shows significant absorption from CO₂ and H₂O and detection of SO₂.

An analysis of transits of planets over starspots on the Sun-like star Kepler-30 shows that the orbits of the three planets are aligned with the stellar equator; this configuration is similar to that of our Solar System, and suggests that high obliquities are confined to systems that experienced disruptive dynamical interactions.

Evidence of a large temperature difference between dawn and dusk has been observed on the exoplanet WASP-107 b. This planet is so cool that it was not expected to exhibit this phenomenon, implying a need to further explore the exoplanet population.

Analysis of the panchromatic transmission spectrum of the warm, low-density, Neptune-sized exoplanet WASP-107b from instruments aboard the HST and JWST suggests that tidal interaction with its host star led to changes in its atmospheric chemistry.

Transmission and emission spectra of the 825 K warm Jupiter WASP-80b taken with the NIRCam instrument of the JWST show strong evidence of CH₄ at greater than 6σ significance

Observations from the JWST show the presence of a spectral absorption feature at 4.05 μm arising from SO₂ in the atmosphere of the gas giant exoplanet WASP-39b, which is produced by photochemical processes and verified by numerical models.

Observations from the James Webb Space Telescope suggest that the exoplanet TRAPPIST-1 b has little or no planetary atmosphere and no detectable atmospheric absorption of carbon dioxide.

The C/O ratio of the transiting hot Jupiter WASP-77Ab is measured here and found to be approximately solar, though the (C+O)/H ratio is subsolar.

A comprehensive study of the Kepler-138 system reveals the twin nature of Kepler-138 c and d and the presence of a fourth planet. Remarkably, the warm-temperate planet Kepler-138 d is probably composed of 50% volatiles by volume, indicative of a water world, rather than a rocky world, despite its small ~1.5 R_⊕ size.

Laboratory experiments where meteorites are heated up to 1,200 °C are performed in order to inform on the outgassing from exoplanetary interiors. Differing considerably from assumptions commonly used by models, the experiments indicate that terrestrial planets would form water-rich steam atmospheres with substantial amounts of CO₂ and CO.

When an extrasolar planet passes in front of its star (transits), its radius can be measured from the decrease in starlight and its orbital period from the time between transits. This study reports Kepler spacecraft observations of a single Sun-like star that reveal six transiting planets, five with orbital periods between 10 and 47 days plus a sixth one with a longer period. The five inner planets are among the smallest for which mass and size have both been measured, and these measurements imply substantial envelopes of light gases.

Photochemical hazes in exoplanet atmospheres work as opacity barriers, hindering characterization of the atmospheres themselves. Here laboratory experiments quantify the haze surface energies that factor into the removal of hazes from atmospheres, which, when added to existing data on haze production, give a greater understanding of haze properties.

Transmission spectroscopy observations from the James Webb Space Telescope show the detection of carbon dioxide in the atmosphere of the gas giant exoplanet WASP-39b.

The molecular mechanisms leading to heart failure in patients with Duchenne muscular dystrophy are unclear. Here the authors show that NF-κB is activated in the heart of dystrophin-deficient mice and that its ablation rescues cardiac function through chromatin remodeling and activation of gene expression.

A population study of near-infrared spectra of 19 hot giant planets shows a correlation between the strength of the 1.4 μm water band and temperature, which is broadly regulated by irradiation. However, the observed scatter around the mean is indicative of the effect of individual planetary formation pathways on the composition.

Exoplanetary and Solar System science lost a major figure with the sudden passing of Professor Adam Showman on 16 March 2020 at the age of 51. He was recognized as the world’s leading authority in the field of atmospheric dynamics of exoplanets.

Space telescope observations of the transmission spectrum of the extrasolar planet HAT-P-11b, which is about the same size as Neptune, reveal water vapour absorption at a wavelength of 1.4 micrometres and indicate that the planetary atmosphere is predominantly clear down to an altitude corresponding to about 1 millibar.

A spectroscopic comparison of ten hot-Jupiter exoplanets reveals that the difference between the planetary radius measured at optical and infrared wavelengths allows atmosphere types ranging from clear to cloudy to be distinguished; the difference in radius at a given wavelength correlates with the spectral strength of water at that wavelength, suggesting that haze obscures the signal from water.

A detailed microphysical model shows that there are two distinct regimes in the aerosol composition of exoplanetary atmospheres: silicates dominate at atmospheric temperatures above 950 K, whereas hydrocarbons prevail for temperatures below 950 K.

The Origins Space Telescope, one of four large Mission Concept Studies sponsored by NASA for review in the 2020 US Astrophysics Decadal Survey, will open unprecedented discovery space in the infrared, unveiling our cosmic origins.

Doppler spectroscopic measurements of the mass of the Earth-sized planet Kepler-78b reveal that its mean density is similar to Earth’s, suggesting a composition of rock and iron.

Cataloging microbial genomes from Earth’s environments expands the known phylogenetic diversity of bacteria and archaea.

This paper reports 8-µm photometric observations of the planet HD 80606b during a 30-hour interval bracketing the periastron passage of its extremely eccentric 111.4 day orbit. As the planet received its strongest irradiation its 8-µm brightness temperature increased from ∼800 K to ∼1500 K over a six-hour period. The radiative time constant at the planet's 8-µm photosphere is ∼4.5 hours, as compared to 3–5 days in Earth's stratosphere.

Global circulation theory predicts strong equatorial jets at the equators of hot gas giant exoplanets that blow hot gas to the east, resulting in an eastward hotspot. Here, Dang et al. present a detection of a hotspot significantly offset to the west.

A comprehensive set of Hubble and Spitzer observations reveal a hydrogen-rich, low-metallicity atmosphere on the sub-Neptune exoplanet GJ 3470 b. Water vapour is detected, but the planet is surprisingly depleted in methane, possibly because of photochemical or thermal processes. Sub-millimetre-sized Mie-scattering cloud particles partially attenuate the molecular signatures at short wavelength, but are largely transparent beyond 3 µm.

Any detection of potential biosignature molecules like oxygen and methane needs to be put into the planetary environmental context to understand its actual importance. Such a contextual approach is also essential when considering alternative or agnostic biosignatures on planets and exoplanets.

The giant planet KELT-9b has a dayside temperature of about 4,600 K, which is sufficiently high to dissociate molecules and to evaporate its atmosphere, owing to its hot stellar host.

The JWST has the potential to increase our understanding of terrestrial exoplanets and their atmospheres, but the various signal contaminations need to be isolated and quantified. Using JWST Cycle 1 observations of TRAPPIST-1 as a benchmark, this Perspective proposes a series of steps to use future JWST data efficiently for this purpose.