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Three Earth-sized planets—receiving similar irradiation to Venus and Earth, and ideally suited for atmospheric study—have been found transiting a nearby ultracool dwarf star that has a mass of only eight per cent of that of the Sun. Three planets to watch Theory predicts that terrestrial or rocky planets are likely to be orbiting the lowest-mass stars. This paper reports the detection of a system of three Earth-sized planets transiting a very nearby (12 parsec) ultracool dwarf star of only 8% of the mass of the Sun. The planets are similar in irradiation to Venus and Earth, and particularly well suited for detailed atmospheric characterization. Star-like objects with effective temperatures of less than 2,700 kelvin are referred to as ‘ultracool dwarfs’ 1 . This heterogeneous group includes stars of extremely low mass as well as brown dwarfs (substellar objects not massive enough to sustain hydrogen fusion), and represents about 15 per cent of the population of astronomical objects near the Sun 2 . Core-accretion theory predicts that, given the small masses of these ultracool dwarfs, and the small sizes of their protoplanetary disks 3 , 4 , there should be a large but hitherto undetected population of terrestrial planets orbiting them 5 —ranging from metal-rich Mercury-sized planets 6 to more hospitable volatile-rich Earth-sized planets 7 . Here we report observations of three short-period Earth-sized planets transiting an ultracool dwarf star only 12 parsecs away. The inner two planets receive four times and two times the irradiation of Earth, respectively, placing them close to the inner edge of the habitable zone of the star 8 . Our data suggest that 11 orbits remain possible for the third planet, the most likely resulting in irradiation significantly less than that received by Earth. The infrared brightness of the host star, combined with its Jupiter-like size, offers the possibility of thoroughly characterizing the components of this nearby planetary system.

A longitudinal thermal brightness map of the super-Earth exoplanet 55 Cancri e reveals strong day–night temperature contrast, indicating inefficient heat redistribution consistent with 55 Cancri e either being devoid of atmosphere or having an optically thick atmosphere with heat recirculation confined to the planetary dayside. Night and day on a super-Earth Super-Earth 55 Cancri e is a nearby exoplanet with a diameter less than around twice that of Earth, but a mass that is about eight times Earth's mass. 55 Cancri e is among the best candidates for the study of the nature of a class of exoplanets that is unknown to our Solar System: previous observations of super-Earths have yielded only featureless spectra. Here Brice-Olivier Demory et al . report a longitudinal thermal brightness map of 55 Cancri e in transit across its host star. The map reveals strong day–night temperature contrast, suggesting inefficient heat redistribution consistent with the planet either lacking an atmosphere, or having an optically thick atmosphere with heat recirculation confined to the planetary dayside. Over the past decade, observations of giant exoplanets (Jupiter-size) have provided key insights into their atmospheres 1 , 2 , but the properties of lower-mass exoplanets (sub-Neptune) remain largely unconstrained because of the challenges of observing small planets. Numerous efforts to observe the spectra of super-Earths—exoplanets with masses of one to ten times that of Earth—have so far revealed only featureless spectra 3 . Here we report a longitudinal thermal brightness map of the nearby transiting super-Earth 55 Cancri e (refs 4 , 5 ) revealing highly asymmetric dayside thermal emission and a strong day–night temperature contrast. Dedicated space-based monitoring of the planet in the infrared revealed a modulation of the thermal flux as 55 Cancri e revolves around its star in a tidally locked configuration. These observations reveal a hot spot that is located 41 ± 12 degrees east of the substellar point (the point at which incident light from the star is perpendicular to the surface of the planet). From the orbital phase curve, we also constrain the nightside brightness temperature of the planet to 1,380 ± 400 kelvin and the temperature of the warmest hemisphere (centred on the hot spot) to be about 1,300 kelvin hotter (2,700 ± 270 kelvin) at a wavelength of 4.5 micrometres, which indicates inefficient heat redistribution from the dayside to the nightside. Our observations are consistent with either an optically thick atmosphere with heat recirculation confined to the planetary dayside, or a planet devoid of atmosphere with low-viscosity magma flows at the surface 6 .

Seven rocky planets orbit the nearby dwarf star TRAPPIST-1, providing a unique opportunity to search for atmospheres on small planets outside the Solar System 1 . Thanks to the recent launch of the James Webb Space Telescope (JWST), possible atmospheric constituents such as carbon dioxide (CO 2 ) are now detectable 2 , 3 . Recent JWST observations of the innermost planet TRAPPIST-1 b showed that it is most probably a bare rock without any CO 2 in its atmosphere 4 . Here we report the detection of thermal emission from the dayside of TRAPPIST-1 c with the Mid-Infrared Instrument (MIRI) on JWST at 15 µm. We measure a planet-to-star flux ratio of f p / f ⁎  = 421 ± 94 parts per million (ppm), which corresponds to an inferred dayside brightness temperature of 380 ± 31 K. This high dayside temperature disfavours a thick, CO 2 -rich atmosphere on the planet. The data rule out cloud-free O 2 /CO 2 mixtures with surface pressures ranging from 10 bar (with 10 ppm CO 2 ) to 0.1 bar (pure CO 2 ). A Venus-analogue atmosphere with sulfuric acid clouds is also disfavoured at 2.6 σ confidence. Thinner atmospheres or bare-rock surfaces are consistent with our measured planet-to-star flux ratio. The absence of a thick, CO 2 -rich atmosphere on TRAPPIST-1 c suggests a relatively volatile-poor formation history, with less than 9.5 − 2.3 + 7.5 Earth oceans of water. If all planets in the system formed in the same way, this would indicate a limited reservoir of volatiles for the potentially habitable planets in the system. The detection of thermal emission from the rocky exoplanet TRAPPIST-1 c using the Mid-Infrared Instrument on the James Webb Space Telescope reveals a dayside brightness temperature that disfavours a thick, CO 2 -rich atmosphere.

Two exoplanet atmospheres examined This paper reports Hubble Space Telescope observations of the inner two of three Earth-sized exoplanets that were recently discovered close to the habitable zone of the nearby ultracool dwarf star TRAPPIST-1. The combined transmission spectrum of TRAPPIST-1 b and c was obtained during their simultaneous transits on 4 May 2016. The lack of features in the combined spectrum effectively rules out cloud-free hydrogen-dominated atmospheres for each planet, but they could have a variety of other types of atmosphere, from one consisting mainly of cloud-free water vapour to a Venus-like atmosphere. Three Earth-sized exoplanets were recently discovered close to the habitable zone 1 , 2 of the nearby ultracool dwarf star TRAPPIST-1 (ref. 3 ). The nature of these planets has yet to be determined, as their masses remain unmeasured and no observational constraint is available for the planetary population surrounding ultracool dwarfs, of which the TRAPPIST-1 planets are the first transiting example. Theoretical predictions span the entire atmospheric range, from depleted to extended hydrogen-dominated atmospheres 4 , 5 , 6 , 7 , 8 . Here we report observations of the combined transmission spectrum of the two inner planets during their simultaneous transits on 4 May 2016. The lack of features in the combined spectrum rules out cloud-free hydrogen-dominated atmospheres for each planet at ≥10 σ levels; TRAPPIST-1 b and c are therefore unlikely to have an extended gas envelope as they occupy a region of parameter space in which high-altitude cloud/haze formation is not expected to be significant for hydrogen-dominated atmospheres 9 . Many denser atmospheres remain consistent with the featureless transmission spectrum—from a cloud-free water-vapour atmosphere to a Venus-like one.

Dopamine agonist withdrawal syndrome (DAWS) is a severe condition reported primarily in Parkinson's disease (PD) but increasingly recognized in restless legs syndrome (RLS). While DAWS is classically associated with high-dose dopamine agonists (DAs) in Parkinson's disease, it has also been reported in RLS patients treated with low-dose therapy (≤ 0.75 mg pramipexole equivalent), although such cases remain rare. While direct evidence is lacking, psychological and relational stressors, in conjunction with prior medication adjustments, could plausibly modulate DAWS severity through a mechanism akin to kindling. We describe the case of a 51-year-old male who developed severe DAWS after withdrawing from low-dose pramipexole (0.26 mg) prescribed for RLS. A 6-month venlafaxine taper, completed 2 weeks before DA tapering, may have increased neurochemical vulnerability. Initial dose reduction caused akathisia, tremors, panic attacks, RLS worsening, and depressive symptoms. After brief reinstatement, abrupt cessation triggered painful electric-like sensations in the lower back and emotional collapse. The patient was transitioned to rotigotine (2 mg/day), together with other psychotropic medications, which provided partial and temporary relief. Symptoms relapsed during tapering, with marked worsening occurring in parallel with episodes of severe relational stress within a close personal connection. Clinical assessments explored these interactions as potential psychological stressors, as reported by the patient. Given the temporal association between these stressors and symptom relapses, relational factors may have contributed to the severity and recurrence of DAWS episodes. At 13 months after complete DA discontinuation, the patient has regained nearly full functionality, although episodes of marked fatigue and significant bedtime RLS persists. This case illustrates that DAWS can occur in RLS patients even at low DA doses, with atypical symptoms possibly involving autonomic and central sensitization. Relational stress may significantly exacerbate symptom severity, potentially leading to profound neurological destabilization through mechanisms such as cross-system hypersensitivity or a kindling-like process, as suggested by existing literature. This factor may need to be systematically assessed in DAWS management. As a rare patient-authored account, this report contributes to the understanding of DAWS in non-PD populations and highlights the need for longitudinal research to guide safer withdrawal protocols and integrated care.

SPECULOOS is a ground-based transit survey consisting of six identical 1 m robotic telescopes. The immediate goal of the project is to detect temperate terrestrial planets transiting nearby ultracool dwarfs (late M-dwarf stars and brown dwarfs), which could be amenable for atmospheric research with the next generation of telescopes. Here, we report the developments of the northern counterpart of the project—SPECULOOS Northern Observatory, and present its performance during the first three years of operations from mid-2019 to mid-2022. Currently, the observatory consists of one telescope, which is named Artemis. The Artemis telescope demonstrates remarkable photometric precision, allowing it to be ready to detect new transiting terrestrial exoplanets around ultracool dwarfs. Over the period of the first three years after the installation, we observed 96 objects from the SPECULOOS target list for 6000 hr with a typical photometric precision of 0.5%, and reaching a precision of 0.2% for relatively bright non-variable targets with a typical exposure time of 25 s. Our weather downtime (clouds, high wind speed, high humidity, precipitation and/or high concentration of dust particles in the air) over the period of three years was 30% of overall night time. Our actual downtime is 40% because of additional time loss associated with technical problems.

Temperate Earth-sized exoplanets around late-M dwarfs offer a rare opportunity to explore under which conditions planets can develop hospitable climate conditions. The small stellar radius amplifies the atmospheric transit signature, making even compact secondary atmospheres dominated by N 2 or CO 2 amenable to characterization with existing instrumentation 1 . Yet, despite large planet search efforts 2 , detection of low-temperature Earth-sized planets around late-M dwarfs has remained rare and the TRAPPIST-1 system, a resonance chain of rocky planets with seemingly identical compositions, has not yet shown any evidence of volatiles in the system 3 . Here we report the discovery of a temperate Earth-sized planet orbiting the cool M6 dwarf LP 791-18. The newly discovered planet, LP 791-18d, has a radius of 1.03 ± 0.04  R ⊕ and an equilibrium temperature of 300–400 K, with the permanent night side plausibly allowing for water condensation. LP 791-18d is part of a coplanar system 4 and provides a so-far unique opportunity to investigate a temperate exo-Earth in a system with a sub-Neptune that retained its gas or volatile envelope. On the basis of observations of transit timing variations, we find a mass of 7.1 ± 0.7  M ⊕ for the sub-Neptune LP 791-18c and a mass of 0.9 − 0.4 + 0.5 M ⊕ for the exo-Earth LP 791-18d. The gravitational interaction with the sub-Neptune prevents the complete circularization of LP 791-18d’s orbit, resulting in continued tidal heating of LP 791-18d’s interior and probably strong volcanic activity at the surface 5 , 6 . The authors report on a temperate Earth-sized planet orbiting the cool M6 dwarf LP 791-18 with a radius of 1.03 ± 0.04  R ⊕ and an equilibrium temperature of 300–400 K, with the permanent night side plausibly allowing for water condensation.

The TRAPPIST-1 system contains seven roughly Earth-sized planets locked in a multiresonant orbital configuration 1 , 2 , which has enabled precise measurements of the planets’ masses and constrained their compositions 3 . Here we use the system’s fragile orbital structure to place robust upper limits on the planets’ bombardment histories. We use N -body simulations to show how perturbations from additional objects can break the multiresonant configuration by either triggering dynamical instability or simply removing the planets from resonance. The planets cannot have interacted with more than ~5% of one Earth mass ( M ⊕ ) in planetesimals—or a single rogue planet more massive than Earth’s Moon—without disrupting their resonant orbital structure. This implies an upper limit of 10 −4 M ⊕ to 10 −2   M ⊕ of late accretion on each planet since the dispersal of the system’s gaseous disk. This is comparable to (or less than) the late accretion on Earth after the Moon-forming impact 4 , 5 , and demonstrates that the growth of the TRAPPIST-1 planets was complete in just a few million years, roughly an order of magnitude faster than that of the Earth 6 , 7 . Our results imply that any large water reservoirs on the TRAPPIST-1 planets must have been incorporated during their formation in the gaseous disk. The resonant chain of the TRAPPIST-1 planets is dynamically fragile, as small perturbations during its lifetime would have disrupted it. N -body simulations show that the system could not have interacted with more than 0.05 Earth masses of material after its formation. Thus, any water in the planets must come from the planets’ original accretion.

Asteroid discoveries are essential for planetary-defence efforts aiming to prevent impacts with Earth 1 , including the more frequent 2 megaton explosions from decametre impactors 3 , 4 , 5 – 6 . Although large asteroids (≥100 kilometres) have remained in the main belt since their formation 7 , small asteroids are commonly transported to the near-Earth object (NEO) population 8 , 9 . However, owing to the lack of direct observational constraints, their size–frequency distribution (SFD)—which informs our understanding of the NEOs and the delivery of meteorite samples to Earth—varies substantially among models 10 , 11 , 12 , 13 – 14 . Here we report 138 detections of some of the smallest asteroids (≳10 metres) ever observed in the main belt, which were enabled by JWST’s infrared capabilities covering the emission peaks of the asteroids 15 and synthetic tracking techniques 16 , 17 – 18 . Despite small orbital arcs, we constrain the distances and phase angles of the objects using known asteroids as proxies, allowing us to derive sizes through radiometric techniques. Their SFD shows a break at about 100 metres (debiased cumulative slopes of q  = −2.66 ± 0.60 and −0.97 ± 0.14 for diameters smaller and larger than roughly 100 metres, respectively), suggestive of a population driven by collisional cascade. These asteroids were sampled from several asteroid families—most probably Nysa, Polana and Massalia—according to the geometry of pointings considered here. Through further long-stare infrared observations, JWST is poised to serendipitously detect thousands of decametre-scale asteroids across the sky, examining individual asteroid families 19 and the source regions of meteorites 13 , 14 ‘in situ’. Combining the infrared capabilities of JWST and synthetic tracking techniques, the detection of some of the smallest asteroids ever observed in the main belt is reported; their large abundance reveals a population driven by collisional cascade.

Circumbinary planets, those that orbit around both stars of a central binary star system, challenge our understanding of planet formation. With only 12 binary systems known to host circumbinary planets, identifying more of these planets, along with their physical properties, could help to discern some of the physical processes that govern planet formation. Here we analyse radial-velocity data obtained by the HARPS and ESPRESSO spectrographs and report the detection of BEBOP-1 c, a gas giant planet with a mass of 65.2 ± 11.8 Earth masses (M⊕) orbiting around both stars of an eclipsing binary star system with a period of 215.5 ± 3.3 days. The system TOI-1338, hereafter referred to as BEBOP-1, which also hosts the smaller and inner transiting planet TOI-1338 b, is only the second confirmed multiplanetary circumbinary system. We do not detect TOI-1338 b with radial-velocity data alone, and we can place an upper limit on its mass of 21.8 M⊕ with 99% confidence. TOI-1338 b is amenable to atmospheric characterization using JWST, so the BEBOP-1 system has the potential to act as a benchmark for circumbinary exo-atmospheric studies.The radial-velocity technique could detect a small gas giant orbiting a binary star and determine its mass: 65.2 ± 11.8 Earth masses. The system also hosts a smaller inner planet, making it one of the few known multiplanetary circumbinary systems.