Planets are thought to form from dust and gas in protoplanetary disks, with debris disks being the remnants of planet formation. Aged a few million up to a few billion years, debris disks have lost their primordial gas, and their dust is produced by steady-state collisions between larger, rocky bodies1,2. Tens of debris disks, with sizes of tens, sometimes hundreds, of astronomical units have been resolved with high-spatial-resolution, high-contrast imagers at optical and near-infrared or (sub)millimetre interferometers3,4. They commonly show cavities, ring-like structures and gaps, which are often regarded as indirect signatures of the presence of planets that gravitationally interact with unseen planetesimals2,5. However, no planet responsible for these features has been detected yet, probably because of the limited sensitivity (typically 2–10MJ) of high-contrast imaging instruments (see, for example, refs.6,7,8,9) before the James Webb Space Telescope. Here we have used the unprecedented sensitivity of the James Webb Space Telescope’s Mid-Infrared Instrument10,11in the thermal infrared to search for such planets in the disk of the approximately 6.4-Myr-old star TWA 7. With its pole-on orientation, this three-ring debris disk is indeed ideally suited for such a detection. We unambiguously detected a source 1.5 arcsec from the star, which is best interpreted as a cold, sub-Jupiter-mass planet. Its estimated mass (about 0.3MJ) and position (about 52au, de-projected) can thoroughly account for the main disk structures.
The disk around TWA 7 is one of the youngest (6.4 ± 1 Myr old; ref.12) debris disks known to date. TWA 7 is a close (about 34 pc; ref.13), low-mass (0.46M☉; ref.14) member of the young TW Hydra association, sometimes classified as a weak-line, non-accreting T-Tauri star15. The disk, resolved by the Near Infrared Camera and Multi-Object Spectrometer (NICMOS) on the Hubble Space Telescope (HST)16, is one of the rare ones resolved around M stars. It is seen almost pole-on17,18, a most favourable configuration to precisely estimate its radial distribution and to look for planets. The most recent modelling of the disk surface density deduced from polarimetric data from the Spectro-Polarimetic High Contrast Imager for Exoplanets Research (SPHERE) on the Very Large Telescope (VLT)18includes a ring peaking at 28auand extending out to more than 100au(R1), a narrow (less than 7aufull-width at half-maximum) ring at 52au(R2) and a broader (more than 40aufull-width at half-maximum) structure (93au; R3; Figs. 1 and 4 from ref.18). No planet has been detected so far, with detection limits roughly estimated to 0.5–1 MJbeyond 50au(Extended Data Fig.6andSupplementary Information).
The coronagraphic images of TWA 7 taken with the F1140C filter (central wavelength = 11.3 μm, bandwidth = 0.8 μm) of the Mid-Infrared Instrument (MIRI) on the James Webb Space Telescope (JWST)19were obtained on 21 June 2024 during cycle 2 (ID 3662; principal investigator, A.-M.L.; Extended Data Table1). The details on the data reduction procedure are described in theMethods. The main critical step is the subtraction of the residual diffracted light leaking from the MIRI coronagraph using a reference star observed with the same set-up. This process is necessary to bring the contrast ratio with respect to the star to a level of 10−5–10−4beyond angular separations of about 0.5 arcsec. The final image, presented in Fig.1, reveals three sources within 10 arcsec from TWA 7, the properties of which are listed in Extended Data Table2. One source at about 4.7 arcsec from TWA 7 (position angle 107°) was classified as a stellar background source, already detected in ancillary optical data from the Space Telescope Imaging Spectrograph (STIS) on the HST as well as near-infrared data from the NICMOS on the HST and the SPHERE on the VLT. The second one, located about 6.7 arcsec east of TWA 7, and spatially resolved, has no counterpart in the data from the SPHERE on the VLT, or in the data from the NICMOS or the STIS on the HST (taking into account TWA 7 proper motion (−118.751 ± 0.023 mas yr−1, −19.648 ± 0.026 mas yr−1; ref.20)). Its location in the MIRI image is consistent with that of a bright source in Atacama Large Millimeter Array (ALMA) band 7 (346 GHz) data from 2016 (ref.21), given the proper motion of the TWA 7 system between the ALMA and MIRI observations. This object therefore has the characteristics of a highly reddened background source. It is reminiscent of the JWST observations of the HR 8799 multi-planetary system, for which az≈ 1 galaxy was detected in the MIRI data taken at both 10 and 15 μm, and in ALMA band 7 data as well, but never identified in the near-infrared22. The third source, located about 1.5 arcsec northwest of TWA 7 (about 51au, projected separation) is unique to these MIRI observations. Hence, this source (hereafter, CC#1) is extremely red, and is not compatible with any background or foreground star.
North is up, and east is left. The status of three identified sources is indicated. Note that the faint signal north of the background galaxy is an artefact. bgd, background.
No data are available to test whether this third source shares a common proper motion with the star. In this context, in the following, we discuss the possible nature of this object. The first origin that one can consider is a Solar System object. Yet, most Solar System objects have proper motion between 5 and 40 arcsec h−1(ref.23). Even very remote, low-proper-motion small Solar System objects such as the dwarf planets Eris (semi-major axis of about 68au) and Sedna (semi-major axis of about 510au) showed proper motion of 1.4 arcsec h−1(ref.24) and 1.7 arcsec h−1(ref.25), respectively, at the time of their discovery. No trail was observed during the 2-h-long exposures, and no apparent motion was observed between the two images recorded during the sequences taken 2 h apart, indicating that CC#1 has a proper motion of less of than about 0.05 arcsec h−1. A Solar System object with such a low proper motion would be located at more than 200au. For such a cold object, reflected light would dominate in the MIRI F1140C filter and would require a Neptune-like size to fit the flux measured for CC#1 (for a geometric albedo of 0.1–0.3). It was checked whether such a scenario could be compatible with the hypothetical Planet Nine26. On the basis of the constraints from the planetary ephemeris27and the predictions of the orbit of Planet Nine28, a Solar System origin for CC#1 can definitely be excluded.
The second possible origin is a background galaxy. Like the background galaxy seen east of TWA 7, CC#1 has no reported counterpart at optical and near-infrared wavelengths. However, in contrast to this galaxy, it has no detected counterpart in the ALMA band 7 data (see details inSupplementary Information). The detection of this unresolved source at 11.3 μm, its non-detection in ALMA band 7 and the measured upper limits at 1.6 μm in the data from the SPHERE on VLT (Supplementary Information) could still be compatible with intermediate-redshift star-forming galaxies. Using such galaxy templates at various redshifts and published galaxy counts in JWST fields of view, we estimated that the probability of finding one such galaxy in a region of 1.5 arcsec radius centred on TWA 7 is about 0.34% (Methods). This probability is low, albeit non-zero. The location of the source with respect to the disk structure, right in a circumstellar ring gap (see below), makes the galaxy hypothesis even more unlikely.
The third and last possible origin is a planet. A forward modelling approach is used to constrain the properties of this planet. Using the HADES model29, it is possible to find fits for the JWST photometric data point while accounting for the 5σupper limits provided by the high-contrast images at 1.59 μm (H2) and 1.67 μm (H3) from the SPHERE on the VLT (Fig.2). HADES considers the thermal evolution of the planet; it assumes that the planet and the stars are coeval. Atmospheric fits incorporating water clouds indicate a narrow range, regardless of other parameters, for the effective temperature between 305 and 335 K (Extended Data Fig.3and Extended Data Table3), and a mass of about 0.3MJ. A metallicity range above solar is required. Additional data will be necessary to further constrain this parameter.
Modelled photometry is shown with crosses. The 1–15-μm spectra correspond to representative solutions that fit the observed flux of TWA 7b in the JWST F1140C filter (blue), with respect to the 5σupper limits from the VLT SPHERE data in the H2 and H3 filters (red), and are consistent with an age of 6.4 ± 1 Myr. The bandwidths of H2 and H3 are 0.052 μm and 0.054 μm, respectively. A zoomed-in view around H2 and H3 highlights their bandwidths and the integrated model spectrum points below the upper limit. met, metallicity;Teff, effective temperature;fsed, sedimentation rate.
As a comparison and extra mass estimation, evolutionary models of cold, low-mass planets30combined with our estimation of effective temperature are used; they lead to a comparable mass of close to 0.3MJ(Extended Data Fig.4) for metallicities less than 2.5, as available in their framework. These two consistent results indicate that the planet mass is substantially below 1MJ. The current best estimate is around 0.3MJ, and is only weakly dependent on the underlying details of the two models used. It, however, depends on the age of the planet, assumed here to be coeval with its parent star. A younger planet would lead to a smaller mass.
The observed source is located right on the R2 narrow ring, and, moreover, within a region identified by ref.18as underdense compared to the rest of the ring (Fig.3a). This is very reminiscent of simulations of resonant rings predicted by early works31,32for closer and less massive planets, which led to the proposal of such a possible situation for the TWA 7 system18.
a, Polarimetric image (in log scale) of the disk composed of the sum of three epochs (26 April 2016 presented in ref.17, 20 March 2017 presented in ref.18, and a new epoch, 8 February 2022, reduced as in ref.18) from the SPHERE Infrared Dual-Band Imager and Spectrograph (IRDIS), with the MIRI image (resampled to the SPHERE pixel size) as an overlay with contours. The log of these data is provided in Supplementary Table2. The peak densities of the rings are also indicated. The central hatched disk is a numerical mask to hide the stellar residuals.b, Disk simulations. Top view of a disk of massless planetesimals perturbed by a 0.34-MJplanet at 52au, on a circular orbit, after 6 Myr (see details in text). The orbit of the perturbing planet is sketched in green and the location of the planet on its orbit is shown in red.
DedicatedN-body simulations were conducted for a planet with a mass of 0.34MJ, located at 52auaround the 0.46M☉central star. This value is consistent with the measured projected separation, assuming that the planet and the ≈13°-inclined disk are coplanar. The simulation also included a disk of 200,000 planetesimals, distributed between 20 and 130au. These parameters were selected to roughly match the boundaries of the observed disk. The planetesimal disk was assumed to be coplanar with the planet’s orbit, with an initial surface density proportional to 1/r. The eccentricities of the planetesimals were chosen to range between 0 and 0.01, and the planet was assumed to evolve on a circular orbit. The simulations, which spanned 10 Myr, were performed using the symplecticN-body code swift_rmv3 (ref.33), which provides a first-order treatment of close encounters.
A top view of the resulting distribution of planetesimals after 6 Myr is shown in Fig.3b. Planetary perturbations efficiently carve the disk over about 30au, but leave a narrow ring at 52au, as well as a relative void (underdensity) around the planet. The latter structure is characteristic of a ring of co-orbital planetesimals with the planets, trapped in a 1:1 resonance with it. The similarity between the TWA 7 disk image and the simulation (Fig.3a,b) is remarkable. In this context, the observed R2 ring would correspond to the ring of co-orbiters with the planet. We nevertheless expect some differences between both distributions owing to the radiation pressure acting on the grains. Additional information on the grain size distribution is needed to compute the effects of radiation pressure and refine the dynamical modelling.
The low likelihood of a background galaxy, the successful fit of the MIRI flux and SPHERE upper limits by a 0.3-MJplanet spectrum and the fact that an approximately 0.3-MJplanet at the observed position would naturally explain the structure of the R2 ring, its underdensity at the planet’s position and the gaps provide compelling evidence supporting a planetary origin for the observed source. Like the planet β Pictoris b, which is responsible for an inner warp in a well-resolved—from optical to millimetre wavelengths—debris disk34, TWA 7b is very well suited for further detailed dynamical modelling of disk–planet interactions. To do so, deep disk images at short and millimetre wavelengths are needed to constrain the disk properties (grain sizes and so on). Refining the planet mass determination can be carried out with additional JWST photometry and possibly spectroscopy. Measuring the orbital parameters (eccentricity, in particular) is more challenging given the long orbital period (about 550 yr) of the planet. Yet, one notes that a planet on an eccentric orbit would rapidly destroy R2.
As it is angularly well resolved from the star, TWA 7b is suited for direct spectroscopic investigations, providing the opportunity to study the interior and the atmosphere of a non-irradiated sub-Jupiter-mass, cold (about 320 K) exoplanet, and start comparative studies with our much older and cooler Solar System giants, as well as with the recently imaged cold (about 275 K) but more massive (6MJ) planet eps Ind Ab35. Improved estimations of its metallicity and temperature will further constrain its mass.
The present results show that the JWST MIRI has opened up a new window in the study of sub-Jupiter-mass planets using direct imaging. Indeed, TWA 7b (about 100M⊕) is at least ten times lighter than the exoplanets directly imaged so far, and planets as light as 25–30M⊕could have been detected if present at 1.5 arcsec from the star or beyond.
Coronagraphic observations were performed with the 4QPM_1140 coronagraph paired with the F1140C filter. The details of the observations are given in Extended Data Table1. We obtained two roll angles (difference of 7.835°) to mitigate the attenuation of the coronagraph in the field of view, in case an object falls close to one phase transition of the 4QPM. Each coronagraphic observation was 2 h long, hence a total of 4 h on the science target. Background observations were observed immediately after the science exposures in a two-point dithering mode, for a total of 4 h.
A reference star, CD-23-9765, was observed back-to-back with the target in the same configuration with the aim to subtract the starlight diffraction after the coronagraph. The reference shares similar brightness and spectral type with the target, and is angularly close. It was observed with nine-point small-grid dithering (SGD) to apply post-processing algorithms such as principal component analysis (PCA)36. In total, the reference star was observed for about 1 h and comes with dedicated background observations.
Using comparison with simulated coronagraphic images, as in ref.37, we were able to estimate a pointing accuracy on the 4QPM of about 2 mas per axis, significantly lower than the 10-mas step of the SGD. We also confirmed the detector coordinates of the 4QPM_1140 mask (119.758, 112.158 as provided in the JWST Calibration Reference Data System).
The data reduction follows the steps described in refs.21,38. Level 1 data are retrieved from the Mikulski Archive for Space Telescopes (MAST), processed with v1.14.0 of the pipeline together with Calibration Reference Data System file 1241. Images are registered to the coronagraph centre. Calibrated files (‘cal’ files) are produced in-house with the JWST pipeline for each roll, by subtracting the background and converting the photometric units (data numbers per second to mega-janskys per steradian). The background is built from the minimum per pixel of the two dithers. We skipped the flat-field correction, which is not appropriate for the MIRI coronagraph22.
We took advantage of the diversity brought by the SGD mode to build a reference frame to subtract the stellar diffraction. We tested various algorithms and retained a linear combination (which uses the downhill simplex minimization) of the nine SGD reference star images, as well as the PCA, as the two algorithms providing the best detection of CC#1. To mitigate the over-subtraction effect, a numerical masking is implemented to ignore some parts of the image. We obtained the best compromise by selecting the annular region between 0.5 arcsec and 3 arcsec, and the three sources were masked with a 1λ/Dpatch, withλrepresenting the observing wavelength andDthe telescope diameter (we checked that the CC#1 flux measurements are similar with a different region: 2–3 arcsec). We proceeded similarly for the PCA, using eight components to build the final image that is subtracted to the data, in an annular region from 0.5 arcsec to 5 arcsec (point sources not masked). Despite the bad-pixel correction applied on the raw coronagraphic images, the subtracted images with the reference star are still affected by a few bad pixels, both with the linear combination and PCA. We further apply aσ-clipping function to correct for these remaining bad pixels. Finally, the images are rotated to align north up, considering the aperture position angles: 121.45° for roll 1 and 129.27° for roll 2, as well as the V3 axis orientation on the detector (4.835°).
Next, extracting the flux and position of the CC#1 requires modelling its point spread function (PSF), which can vary spatially and nonlinearly owing to the attenuation of the coronagraph for which the phase transitions extend across the whole field of view. We used both the diffraction code developed in refs.39,40and WebbPSF41to simulate the MIRI PSF, taking into account the coronagraph, considering the configuration of mask, stop and filter (‘FQPM1140’, ‘MASKFQPM’ and ‘F1140C’, according to the WebbPSF terminology). The position of CC#1 is approximated with a Gaussian fit, passing the sky coordinates to the former diffraction code and detector coordinates to WebbPSF to calculate the PSF of CC#1 accounting for the coronagraph attenuation. We measured the coronagraph transmission with both PSF estimates. The flux of the PSF model at the position of CC#1 is integrated in a 1.5λ/Daperture (to match the aperture used for photometric measurements), and compared to that at 10 arcsec (far away from the coronagraph influence). The two approaches give similar transmissions: 0.66 and 0.62 in roll 1 and 0.31 and 0.28 in roll 2. Therefore, CC#1 is significantly closer to one 4QPM transition in roll 2 than in roll 1, so both its astrometry and photometry can be affected (Extended Data Fig.1). We measured a signal-to-noise ratio of 30 and 18, respectively, for roll 1 and roll 2, using the linear combination method. In the roll 2 image, the PSF is more asymmetrical as the planet is closer to the quadrant edge in comparison to roll 1, so we decided to consider only roll 1 data for the photometric analysis.
On the basis of these CC#1 PSF models, we extracted the flux and the photometry of the object by minimizing the residuals between the reduced JWST data and a PSF model in a 1.5λ/Darea with three free parameters (positions and flux) and using either a downhill simplex algorithm or the Nelder–Mead algorithm42. For comparison, we also used aperture photometry, but this required implementation of an aperture correction based on simulated PSF (ratio of the total flux in the PSF to the flux integrated in the 1.5λ/Daperture).
The flux extraction is applied both on the photometrically calibrated files (.cal), which directly provides CC#1 flux in mega-janskys per steradian, and on the uncalibrated files (.rate), which requires to measure a contrast with respect to the non-coronagraphic image of the star. As detailed previously22, the contrast measurement relies on commissioning data either on target acquisition images that come with the telescope pointing procedure but are obtained with a neutral density filter, or from images obtained on and off the coronagraph on another star. The method using target acquisition shows some net discrepancies, probably because the target acquisition filter is very broad (about 8–18 μm) and the targets have different spectral types (M3 for TWA 7 and K0 or K5 for the commissioning targets). Besides, the emission of the TWA 7 disk is expected to become significant beyond 15 μm. As a result, we did not use the target acquisition method in the following. The final photometric values are based on the linear combination and PCA technique to suppress the starlight. We averaged the values of the different methods (calibrated files and contrast, aperture and PSF model for the photometric extraction) and the error bar is built from the extreme values ((max − min)/2) for being conservative. We measured a flux density of 5.60 ± 0.97 × 10−19W m−2μm−1for CC#1. The fluxes of the other sources are given in Extended Data Table2. Note that we also tested the typical ‘injection–recovery’ method directly in the raw data, but did not notice any significant differences for the extracted flux of the planet.
To estimate the probability that the source labelled CC#1 is a galaxy, we have taken into account the three constraints on the fluxes or upper limits at 1.6, 11 and 870 μm. The source has a flux of 22 μJy at 11 μm, and is not detected with ALMA at 870 μm, but with a tapered resolution of 2 arcsec. The measured 3σupper limit for an unresolved source at the position of the MIRI source is 96 μJy (ref.21). Combining all ALMA observations (see Extended Data Fig.5), the 3σupper limit is 76 μJy, in a beam of 0.29 arcsec × 0.24 arcsec (see a detailed analysis and estimation in theSupplementary Information). The third constraint is from the non-detection at 1.6 μm with VLT SPHERE, with an upper limit of approximately 0.6 μJy for a point source (about 60 mas in size). However, we have to take into account the fact that a low-zgalaxy could be extended in the calculation of its maximum flux at 2 μm. Indeed, the size of a galaxy is expected to vary from one wavelength to the other: at 1.6 μm, the disk of old stars dominates, so the source is more extended, of the order of 10 kpc, whereas at 11 μm and 870 μm, the nuclear star-forming region dominates, and will appear more concentrated, of the order of 100–500 pc. We therefore considered the flux limit of an extended (0.6 arcsec) source in the SPHERE data (that is, 60 μJy).
Two types of galaxy might comply with these three constraints: star-forming galaxies or active nucleus (AGN) or a combination of both, with a redshift betweenz= 0.1 and 1. For such galaxies, at lower redshifts, where 1 arcsec is smaller than 2 kpc, the source would probably look extended (up to 5 arcsec) for wavelengths between 1 and 4 μm (ref.43). At higher redshifts, the peak of the emission usually located at 100 μm will enter the ALMA domain at about 1 mm, and it should have been detected by ALMA44.
As the density of the cosmic star formation rate increases considerably with redshift betweenz= 0 and 1, starbursts atz= 0 are good templates for star-forming galaxies atz= 0.1 to 1. The starburst is in general nuclear. It can be highly peaked in the centre, or distributed in a ring of about 100-pc radius (like in M82), but the emitting size at 100-μm rest frame will be no more than typically 1 kpc. This corresponds to an angular size of about 0.55 arcsec atz= 0.1, about 0.16 arcsec atz= 0.5, and about 0.12 arcsec atz= 1. We also considered AGN templates. The nucleus is then a point source at long wavelengths, while the galaxy host is extended (about 10 kpc) at the shortest wavelengths.
The probability to find az= 0.1 to 1 star-forming galaxy with a flux at 11 μm of 22 ± 3.8 μJy (hence, within a range of 7.6 μJy) in a field of view of 10 × 10 arcsec can be estimated readily through the source counts, from refs.45,46,47,48. A probability of 50% is found in the redshift rangez= 0.1 to 1.
To take into account the other constraints at 1.6 and 870 µm, we used the Spitzer Wide-Area Infrared Extragalactic Survey (SWIRE) templates, from ref.49,http://www.iasf-milano.inaf.it/~polletta/templates/swire_templates.htmlwhich include 14 templates of starbursts and AGN, representative of star-forming and active intermediate-redshift galaxies. These templates were computed for a half-dozen redshifts, and calibrated to have a flux of 22 μJy at 11 μm. An illustrative plot of their spectral energy distribution (SED) is shown in Extended Data Fig.2, in which the flux constraints at 1.6 and 870 µm are also indicated by black symbols (square and triangle).
We used the rest-frame 8-μm luminosity function of galaxies at redshifts betweenz= 0.1 andz= 1 in the Great Observatories Origins Deep Survey (GOODS) fields50to estimate the abundance of these star-forming galaxies. The 8-μm luminosity was deduced from the templates. This led to a probability of 12% to find such a galaxy in the right redshift range (z= 0.1 to 1) in the 10 × 10 arcsec field of view. We estimated that there are about 80% star-forming galaxies and 20% active nuclei, including low-luminosity ones such as Seyfert galaxies51,52. As can be seen in Extended Data Fig.2, all templates comply with the three constraints belowz= 0.5, and some starbursts are found brighter at 870 μm above this redshift. We therefore reduced the probability accordingly forz> 0.5, attributing each star-forming template equal probability, as shown by the observations53. The final probability to find such a galaxy in the 10 × 10 arcsec field of view is about 5%, with significant uncertainties: +3/−2%. Hence, in a radius of 1.5 arcsec around TWA 7, the probability to have such a galaxy is about 0.34% (+0.22/−0.14%). We note that the distribution of galaxies on the sky might be clustered in some rare places, and our error bars should be increased, but no more than 30% given the typical errors on luminosity function of galaxies45,47,50. Altogether, the probability of having a galaxy satisfying the various constraints within 1.5 arcsec would be 0.34% (+0.29/−0.18%). Note that the current calculation applies to these specific observational constraints. The probability for CC#1 to be a rare type of background galaxy compatible with the JWST, ALMA and SPHERE observational constraints is therefore low. Such a low-probability event can admittedly arise would a large number of independent datasets be analysed. However, this is not the case for this study. Indeed, only two datasets among about 30 JWST MIRI datasets dedicated to exoplanet searches are analysed. Moreover, most of the other datasets are not as deep as the present ones, and there are no corresponding 1.6- and 870-μm data available. Hence, the likelihood that any research group would have found such a peculiar background galaxy contaminant within the whole corpus of relevant JWST data is much lower than the simple 10.2% (30 × 0.34%) one could derive.
All observational data in this work are available through public data archives. The JWST data were collected through General Observer programme number 3662 (principal investigator A.-M.L.) and will be available through the MAST database (https://mast.stsci.edu) from 21 June 2025. The data described here are available via the MAST archive athttps://doi.org/10.17909/4qvz-sw62. The present study made use of ALMA data collected during the 2015.1.01015.S programme (principal investigator A. Bayo). The present study made use of detection limits derived from SPHERE data collected during the programme 198.C-0209, and of SPHERE data collected during the programmes 097.C-0319(A), 105.209E.001 and 198.C-0209(F). The data are available athttps://archive.eso.org.
JWST MIRI data reduction and analysis codes are available via GitHub athttps://github.com/mathildemalin/ExoCAT. Data reduction was carried out using the publicly available JWST pipelinehttps://jwst-pipeline.readthedocs.io/en/latest/, and the stpf packagehttps://stpsf.readthedocs.io/en/latest/to simulate PSFs for JWST. We used various functions of the following software packages to perform the analysis and create the figures: numpy, astropy, scipy, matplotlib and photutils.
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This work is based on observations made with the JWST of NASA (National Aeronautics and Space Administration), the European Space Agency and the Canadian Space Agency. The data were obtained from the Mikulski Archive for Space Telescopes at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-03127 for JWST. These observations are associated with programme number 3662. This paper makes use of ALMA data. ALMA is a partnership of the European Organisation for Astronomical Research in the Southern Hemisphere (representing its member states), the National Science Foundation (USA) and the National Institutes of Natural Sciences (Japan), together with the National Research Council of Canada (Canada), the National Science Council and the Academia Sinica Institute of Astronomy and Astrophysics (Taiwan) and the Korea Astronomy and Space Science Institute (Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by the European Organisation for Astronomical Research in the Southern Hemisphere, the National Radio Astronomy Observatory operated by Associated Universities, Inc., and the National Astronomical Observatory of Japan. This paper makes use of observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere. This project has received funding from the European Research Council under the European Union’s Horizon 2020 research and innovation programme (COBREX; grant agreement number 885593). L.M. acknowledges funding by the European Union through the E-BEANS ERC project (grant number 100117693), and by the Irish Research Council under grant number IRCLA-2022-3788. Views and opinions expressed are those of the authors alone and do not necessarily reflect those of the European Union or the ERC Executive Agency. Neither the European Union nor the granting authority can be held responsible for them.
LIRA, Observatoire de Paris, Université PSL, Sorbonne Université, Université Paris Cité, CY Cergy Paris Université, CNRS, Meudon, France
A.-M. Lagrange, C. Wilkinson, A. Boccaletti, C. Perrot, D. Rouan, A. Chomez, B. Charnay, Q. Kral, P. Thebault, F. Kiefer, A. Radcliffe, J. Mazoyer & S. Stasevic
Université Grenoble Alpes, CNRS, IPAG, Grenoble, France
A.-M. Lagrange, H. Beust, A. Chomez, J. Milli & P. Delorme
Department of Physics & Astronomy, Johns Hopkins University, Baltimore, MD, USA
Space Telescope Science Institute, Baltimore, MD, USA
M. Mâlin, A. Carter & K. A. Crotts
School of Physics, Trinity College Dublin, University of Dublin, Dublin, Ireland
Observatoire de Paris, LUX, PSL University, Collège de France, Sorbonne University, CNRS, Paris, France
Observatoire de la Côte d’Azur, Université Côte d’Azur, Nice, France
Centre de Recherche Astrophysique de Lyon, Université Claude Bernard Lyon 1, CNRS, ENS, Saint-Genis-Laval, France
European Southern Observatory, Garching bei Muenchen, Germany
J. Olofsson, A. Bayo & M. Langlois
Département d’Informatique de l’École Normale Supérieure (ENS-PSL, CNRS, Inria), Paris, France
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A.-M.L. led the proposal, the interpretation of the various data and the writing of the paper. A. Boccaletti, M.M. and C.P. designed the JWST MIRI observing sequence, and reduced the data and participated in their interpretation. C.W. conducted the SED fitting. B.C. participated in the vetting of the Solar System origin of the source. A.R., B.C. and S.M. participated in discussions on the SED fitting. A. Chomez provided the SPHERE detection limit maps used in this paper. A. Chomez, O.F., M.L., P.D. and G.C. participated in their interpretation. S.S. and T.B. tried to improve the detection limits using alternative algorithms. J. Milli participated in the building of the proposal, produced the SPHERE polarimetric images and participated the interpretation of the JWST MIRI data. A. Bayo and J.O. provided their analysis of the ALMA data, and participated in their interpretation. L.M. reanalysed the ALMA data and led the interpretation of these data. D.R. and F.C. conducted the estimation of the galaxy background probability. H.B. performed theN-body dynamical simulations. Q.K. and P.T. participated in the writing of the proposal and in the discussion of the disk–planet interactions. J. Mazoyer participated in the discussion of the disk properties. F.K. participated in the analysis of Gaia data, and general discussion. A. Carter and K.C. participated in the discussion on the astrometry of the source. P.R. participated in the proposal writing and the analysis of the data. All authors commented on the manuscript.
Correspondence toA.-M. Lagrange.
The authors declare no competing interests.
Naturethanks the anonymous reviewers for their contribution to the peer review of this work.
Publisher’s noteSpringer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Orientation of the 4QPM and its phase transitions in the sky plane for the two telescope rolls. North is up, East is left.
The curves are distinguished by their colors, and the corresponding labels, valid for all panels. All curves are calibrated to have a flux of 22 mJy at 11 μm. The two additional constraints are marked by black symbols (square and triangle): the flux should be lower than 60 mJy at 1.6 μm, and 96 mJy at 870 μm. The SED which are not consistent with the limits are plotted in dashed lines.
Corner plot of cloudy forward modeling using SPHERE upper limits and age constraints of 6.4+/− 1 Myr. The associated priors are listed in Extended Data Table3. The mass found is 0.34+/− 0.06 MJ(considering errors from the MCMC only). Core given in Earth mass, Tintcorresponds to the intrinsic temperature and fsedthe sedimentation rate of the considered clouds.
Thermal evolution curves from ref.30, showing the effective temperature evolution of cloudy planets with an [Fe/H] of 0.4 dex. The estimated age and effective temperature of TWA 7b supposing the planet and star are coeval is represented by the blue point. The effective temperature used is 316+19/−23K (derived from the forward modeling) and the age 6.4+/− 1 Myr.
Combined ALMA 0.88 mm image of the TWA 7 system obtained with Briggs 0.5 weighting, centered at the phase center of the April compact configuration observations. The background galaxy is clearly detected East of the expected stellar position, at a position consistent with the East source detected by MIRI (black and white circle). The stellar location at each of the 2016 ALMA epochs is shown by the green star (positions largely overlapping), whereas the stellar location at the 2024 MIRI observation is shown by the orange star. The position of the CC#1 source at the epoch of the 2024 MIRI observation is shown by the cyan circle. The image (not primary beam-corrected) has a resolution of 0.19” x 0.18” (shown as the circle in the bottom left of the image) and an RMS noise level of 23 μJy/beam.
Contrast 5-sigma confidence level curves of the SPHERE observation used to compute the upper limits on the candidate companion flux.
Supplementary Notes 1 and 2, Tables 1 and 2 and References.
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Lagrange, AM., Wilkinson, C., Mâlin, M.et al.Evidence for a sub-Jovian planet in the young TWA 7 disk .Nature(2025). https://doi.org/10.1038/s41586-025-09150-4
DOI:https://doi.org/10.1038/s41586-025-09150-4
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