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Demangeon, O. D., Brandeker, A., Olofsson, G. & Walton, N. A. (2024). Asymmetry in the atmosphere of the ultra-hot Jupiter WASP-76 b. Astronomy and Astrophysics, 684, Article ID A27.
Open this publication in new window or tab >>Asymmetry in the atmosphere of the ultra-hot Jupiter WASP-76 b
2024 (English)In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 684, article id A27Article in journal (Refereed) Published
Abstract [en]

Context. WASP-76 b has been a recurrent subject of study since the detection of a signature in high-resolution transit spectroscopy data indicating an asymmetry between the two limbs of the planet. The existence of this asymmetric signature has been confirmed by multiple studies, but its physical origin is still under debate. In addition, it contrasts with the absence of asymmetry reported in the infrared (IR) phase curve.

Aims. We provide a more comprehensive dataset of WASP-76 b with the goal of drawing a complete view of the physical processes at work in this atmosphere. In particular, we attempt to reconcile visible high-resolution transit spectroscopy data and IR broadband phase curves.

Methods. We gathered 3 phase curves, 20 occultations, and 6 transits for WASP-76 b in the visible with the CHEOPS space telescope. We also report the analysis of three unpublished sectors observed by the TESS space telescope (also in the visible), which represents 34 phase curves.

Results. WASP-76 b displays an occultation of 260 ± 11 and 152 ± 10 ppm in TESS and CHEOPS bandpasses respectively. Depending on the composition assumed for the atmosphere and the data reduction used for the IR data, we derived geometric albedo estimates that range from 0.05 ± 0.023 to 0.146 ± 0.013 and from <0.13 to 0.189 ± 0.017 in the CHEOPS and TESS bandpasses, respectively. As expected from the IR phase curves, a low-order model of the phase curves does not yield any detectable asymmetry in the visible either. However, an empirical model allowing for sharper phase curve variations offers a hint of a flux excess before the occultation, with an amplitude of ~40 ppm, an orbital offset of ~ −30°, and a width of ~20º. We also constrained the orbital eccentricity of WASP-76 b to a value lower than 0.0067, with a 99.7% confidence level. This result contradicts earlier proposed scenarios aimed at explaining the asymmetry observed in high-resolution transit spectroscopy.

Conclusions. In light of these findings, we hypothesise that WASP-76 b could have night-side clouds that extend predominantly towards its eastern limb. At this limb, the clouds would be associated with spherical droplets or spherically shaped aerosols of an unknown species, which would be responsible for a glory effect in the visible phase curves.

Keywords
techniques: photometric, planets and satellites: atmospheres, planets and satellites: composition
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:su:diva-228976 (URN)10.1051/0004-6361/202348270 (DOI)001198960100022 ()2-s2.0-85190485487 (Scopus ID)
Available from: 2024-05-13 Created: 2024-05-13 Last updated: 2024-05-13Bibliographically approved
Bonfanti, A., Brandeker, A., Olofsson, G. & Zingales, T. (2024). Characterising TOI-732 b and c: New insights into the M-dwarf radius and density valley. Astronomy and Astrophysics, 682, Article ID A66.
Open this publication in new window or tab >>Characterising TOI-732 b and c: New insights into the M-dwarf radius and density valley
2024 (English)In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 682, article id A66Article in journal (Refereed) Published
Abstract [en]

Context

TOI-732 is an M dwarf hosting two transiting planets that are located on the two opposite sides of the radius valley. Inferring a reliable demographics for this type of systems is key to understanding their formation and evolution mechanisms.

Aims

By doubling the number of available space-based observations and increasing the number of radial velocity (RV) measurements, we aim at refining the parameters of TOI-732 b and c. We also use the results to study the slope of the radius valley and the density valley for a well-characterised sample of M-dwarf exoplanets.

Methods

We performed a global Markov chain Monte Carlo analysis by jointly modelling ground-based light curves and CHEOPS and TESS observations, along with RV time series both taken from the literature and obtained with the MAROON-X spectrograph. The slopes of the M-dwarf valleys were quantified via a support vector machine (SVM) procedure.

Results

TOI-732b is an ultrashort-period planet (P = 0.76837931-0.00000042+0.0000039 days) with a radius Rb = 1.325-0.058+0.057R, a mass Mb = 2.46 ± 0.19 M, and thus a mean density ρb = 5.8-0.8+1.0 g cm-3, while the outer planet at P = 12.252284 ± 0.000013 days has Rc = 2.39-0.11+0.10RMc = 8.04-0.48+0.50M, and thus ρc = 3.24-0.43+0.55 g cm-3. Even with respect to the most recently reported values, this work yields uncertainties on the transit depths and on the RV semi-amplitudes that are smaller up to a factor of ~1.6 and ~2.4 for TOI-732 b and c, respectively. Our calculations for the interior structure and the location of the planets in the mass-radius diagram lead us to classify TOI-732 b as a super-Earth and TOI-732 c as a mini-Neptune. Following the SVM approach, we quantified d log Rp,valley / d logP = -0.065-0.013+0.024, which is flatter than for Sun-like stars. In line with former analyses, we note that the radius valley for M-dwarf planets is more densely populated, and we further quantify the slope of the density valley as d log ρ^valley / d log P = -0.02-0.04+0.12.

Conclusions

Compared to FGK stars, the weaker dependence of the position of the radius valley on the orbital period might indicate that the formation shapes the radius valley around M dwarfs more strongly than the evolution mechanisms.

Keywords
techniques: photometric, techniques: radial velocities, planets and satellites: fundamental parameters, stars: fundamental parameters
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:su:diva-227978 (URN)10.1051/0004-6361/202348180 (DOI)001158428600006 ()2-s2.0-85184519282 (Scopus ID)
Available from: 2024-04-05 Created: 2024-04-05 Last updated: 2024-04-05Bibliographically approved
Singh, V., Brandeker, A., Patel, J. A., Olofsson, G. & Zingales, T. (2024). CHEOPS observations of KELT-20 b/MASCARA-2 b: An aligned orbit and signs of variability from a reflective day side. Astronomy and Astrophysics, 683, Article ID A1.
Open this publication in new window or tab >>CHEOPS observations of KELT-20 b/MASCARA-2 b: An aligned orbit and signs of variability from a reflective day side
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2024 (English)In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 683, article id A1Article in journal (Refereed) Published
Abstract [en]

Context. Occultations are windows of opportunity to indirectly peek into the dayside atmosphere of exoplanets. High-precision transit events provide information on the spin-orbit alignment of exoplanets around fast-rotating hosts.

Aims. We aim to precisely measure the planetary radius and geometric albedo of the ultra-hot Jupiter (UHJ) KELT-20 b along with the spin-orbit alignment of the system.

Methods. We obtained optical high-precision transits and occultations of KELT-20 b using CHEOPS observations in conjunction with simultaneous TESS observations. We interpreted the occultation measurements together with archival infrared observations to measure the planetary geometric albedo and dayside temperatures. We further used the host star’s gravity-darkened nature to measure the system’s obliquity.

Results. We present a time-averaged precise occultation depth of 82 ± 6 ppm measured with seven CHEOPS visits and from the analysis of all available TESS photometry. Using these measurements, we precisely constrain the geometric albedo of KELT-20 b to 0.26 ± 0.04 and the brightness temperature of the dayside hemisphere to K. Assuming Lambertian scattering law, we constrain the Bond albedo to along with a minimal heat transfer to the night side (ϵ = ). Furthermore, using five transit observations we provide stricter constraints of 3 9 ± 1 1 deg on the sky-projected obliquity of the system.

Conclusions. The aligned orbit of KELT-20 b is in contrast to previous CHEOPS studies that have found strongly inclined orbits for planets orbiting other A-type stars. The comparably high planetary geometric albedo of KELT-20 b corroborates a known trend of strongly irradiated planets being more reflective. Finally, we tentatively detect signs of temporal variability in the occultation depths, which might indicate variable cloud cover advecting onto the planetary day side.

Keywords
techniques: photometric, planets and satellites: atmospheres, planets and satellites: gaseous planets, planets and satellites: individual: KELT-20 b, planets and satellites: individual: MASCARA-2 b
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:su:diva-228908 (URN)10.1051/0004-6361/202347533 (DOI)001185001700001 ()2-s2.0-85186624090 (Scopus ID)
Available from: 2024-05-03 Created: 2024-05-03 Last updated: 2024-05-03Bibliographically approved
Pagano, I., Brandeker, A., Olofsson, G. & Walton, N. A. (2024). Constraining the reflective properties of WASP-178 b using CHEOPS photometry. Astronomy and Astrophysics, 682, Article ID A102.
Open this publication in new window or tab >>Constraining the reflective properties of WASP-178 b using CHEOPS photometry
2024 (English)In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 682, article id A102Article in journal (Refereed) Published
Abstract [en]

Context. Multiwavelength photometry of the secondary eclipses of extrasolar planets is able to disentangle the reflected and thermally emitted light radiated from the planetary dayside. Based on this, we can measure the planetary geometric albedo Ag, which is an indicator of the presence of clouds in the atmosphere, and the recirculation efficiency ϵ, which quantifies the energy transport within the atmosphere.

Aims. We measure Ag and ϵ for the planet WASP-178 b, a highly irradiated giant planet with an estimated equilibrium temperature of 2450 K.

Methods. We analyzed archival spectra and the light curves collected by CHEOPS and TESS to characterize the host WASP-178, refine the ephemeris of the system, and measure the eclipse depth in the passbands of the two telescopes.

Results. We measured a marginally significant eclipse depth of 70 ± 40 ppm in the TESS passband, and a statistically significant depth of 70 ± 20 ppm in the CHEOPS passband.

Conclusions. Combining the eclipse-depth measurement in the CHEOPS (λeff = 6300 Å) and TESS (λeff = 8000 Å) passbands, we constrained the dayside brightness temperature of WASP-178 b in the 2250–2800 K interval. The geometric albedo 0.1< Ag<0.35 generally supports the picture that giant planets are poorly reflective, while the recirculation efficiency ϵ >0.7 makes WASP-178 b an interesting laboratory for testing the current heat-recirculation models.

Keywords
planets and satellites: individual: wasp-178 b, techniques: photometric, planets and satellites: detection, planets and satellites: gaseous planets, planets and satellites: atmospheres
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:su:diva-228318 (URN)10.1051/0004-6361/202346705 (DOI)001188262400001 ()2-s2.0-85185216038 (Scopus ID)
Available from: 2024-04-12 Created: 2024-04-12 Last updated: 2024-04-12Bibliographically approved
Sicardy, B., Brandeker, A., Florén, H. G., Olofsson, G. & Kate, A. (2024). Constraints on the evolution of the Triton atmosphere from occultations: 1989-2022. Astronomy and Astrophysics, 682, Article ID L24.
Open this publication in new window or tab >>Constraints on the evolution of the Triton atmosphere from occultations: 1989-2022
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2024 (English)In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 682, article id L24Article in journal (Refereed) Published
Abstract [en]

Context. In about 2000, the south pole of Triton experienced an extreme summer solstice that occurs every ∼650 years, when the subsolar latitude reached about 50°S. Bracketing this epoch, a few occultations probed the Triton atmosphere in 1989, 1995, 1997, 2008, and 2017. A recent ground-based stellar occultation observed on 6 October 2022 provides a new measurement of the atmospheric pressure on Triton. This is presented here.

Aims. The goal is to constrain the volatile transport models (VTMs) of the Triton atmosphere. The atmosphere is basically in vapor pressure equilibrium with the nitrogen ice at its surface.

Methods. Fits to the occultation light curves yield the atmospheric pressure of Triton at the reference radius 1400 km, from which the surface pressure is deduced.

Results. The fits provide a pressure p1400 = 1.211 ± 0.039 μbar at radius 1400 km (47 km altitude), from which a surface pressure of psurf = 14.54 ± 0.47 μbar is deduced (1σ error bars). To within the error bars, this is identical to the pressure derived from the previous occultation of 5 October 2017, p1400 = 1.18 ± 0.03 μbar and psurf = 14.1 ± 0.4 μbar, respectively. Based on recent models of the volatile cycles of Triton, the overall evolution of the surface pressure over the last 30 years is consistent with N2 condensation taking place in the northern hemisphere. However, models typically predict a steady decrease in the surface pressure for the period 2005-2060, which is not confirmed by this observation. Complex surface-atmosphere interactions, such as ice albedo runaway and formation of local N2 frosts in the equatorial regions of Triton, could explain the relatively constant pressure between 2017 and 2022.

Keywords
planets and satellites: atmospheres, planets and satellites: individual: Triton
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:su:diva-228907 (URN)10.1051/0004-6361/202348756 (DOI)001178184800004 ()2-s2.0-85186740734 (Scopus ID)
Available from: 2024-05-03 Created: 2024-05-03 Last updated: 2024-05-03Bibliographically approved
Schwarz, K. R., Henning, T., Christiaens, V., Gasman, D., Samland, M., Perotti, G., . . . Temmink, M. (2024). MINDS. JWST/MIRI Reveals a Dynamic Gas-rich Inner Disk inside the Cavity of SY Cha. Astrophysical Journal, 962(1), Article ID 8.
Open this publication in new window or tab >>MINDS. JWST/MIRI Reveals a Dynamic Gas-rich Inner Disk inside the Cavity of SY Cha
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2024 (English)In: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 962, no 1, article id 8Article in journal (Refereed) Published
Abstract [en]

SY Cha is a T Tauri star surrounded by a protoplanetary disk with a large cavity seen in the millimeter continuum but has the spectral energy distribution of a full disk. Here we report the first results from JWST/Mid-InfraRed Instrument (MIRI) Medium Resolution Spectrometer (MRS) observations taken as part of the MIRI mid-INfrared Disk Survey (MINDS) GTO Program. The much improved resolution and sensitivity of MIRI-MRS compared to Spitzer enables a robust analysis of the previously detected H2O, CO, HCN, and CO2 emission as well as a marginal detection of C2H2. We also report the first robust detection of mid-infrared OH and rovibrational CO emission in this source. The derived molecular column densities reveal the inner disk of SY Cha to be rich in both oxygen- and carbon-bearing molecules. This is in contrast to PDS 70, another protoplanetary disk with a large cavity observed with JWST, which displays much weaker line emission. In the SY Cha disk, the continuum, and potentially the line, flux varies substantially between the new JWST observations and archival Spitzer observations, indicative of a highly dynamic inner disk.

Keywords
Protoplanetary disks, Infrared spectroscopy, James Webb Space Telescope, Molecular spectroscopy
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:su:diva-226716 (URN)10.3847/1538-4357/ad1393 (DOI)001154696400001 ()2-s2.0-85183940754 (Scopus ID)
Available from: 2024-02-16 Created: 2024-02-16 Last updated: 2024-02-16Bibliographically approved
Fridlund, M., Olofsson, G., Brandeker, A., Florén, H. G. & Walton, N. A. (2024). Planets observed with CHEOPS: Two super-Earths orbiting the red dwarf star TOI-776. Astronomy and Astrophysics, 684, Article ID A12.
Open this publication in new window or tab >>Planets observed with CHEOPS: Two super-Earths orbiting the red dwarf star TOI-776
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2024 (English)In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 684, article id A12Article in journal (Refereed) Published
Abstract [en]

Context. M-dwarf stars are the most common of potential exoplanet host stars in the Galaxy. It is therefore very important to understand planetary systems orbiting such stars and to determine the physical parameters of such planets with high precision. Also with the launch of the James Webb Space Telescope (JWST) the observation of atmospheric parameters of planets orbiting these stars has begun. It is therefore required to determine properties of potential targets.

Aims. Two planets around the red dwarf TOI-776 were detected by TESS. The objective of our study was to use transit observations obtained by the CHEOPS space mission to improve the current precision of the planetary radii, as well as additional radial velocity (RV) data in order to improve mass estimates of the two planets. Using these quantities, we wanted to derive the bulk densities of those planets, improving the precision in earlier results, and use this information to put them in context of other exoplanetary systems involving very low mass stars.

Methods. Utilizing new transit data from the CHEOPS satellite and its photometric telescope, we obtained very high precision planetary transit measurements. Interpretation of these provides updated planetary radii, along with other system parameters. A concurrent ESO large observing program using the high precision spectrograph HARPS has doubled the available radial velocity data. Calculating the power spectrum of a number of stellar activity indices we update the previously estimated stellar rotation period to a lower value.

Results. The CHEOPS data provide precise transit depths of 909 and 1177 ppm translating into radii of Rb = R and Rc = R, respectively. Our interpretation of the radial velocities and activity indicator time series data estimates a stellar rotation period for this early M dwarf of ~21.1 days. A further multi-dimensional Gaussian process approach confirm this new estimate. By performing a Skew-Normal (SN) fit onto the Cross Correlation Functions we extracted the RV data and the activity indicators to estimate the planetary masses, obtaining Mb = M and Mc = M.

Conclusions. We improve the precision in planetary radius for TOI-776 b and c by a factor of more than two. Our data and modelling give us parameters of both bodies consistent with mini-Neptunes, albeit with a relatively high density. The stellar activity of TOI-776 is found to have increased by a factor larger than 2 since the last set of observations.

Keywords
techniques: photometric, techniques: spectroscopic, planets and satellites: detection, planets and satellites: individual: TOI-776 b, planets and satellites: individual: TOI-776 c, stars: individual: LP 961-53
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:su:diva-228977 (URN)10.1051/0004-6361/202243838 (DOI)001198847900010 ()2-s2.0-85184520440 (Scopus ID)
Available from: 2024-05-13 Created: 2024-05-13 Last updated: 2024-05-13Bibliographically approved
Dyrek, A., Min, M., Decin, L., Bouwman, J., Crouzet, N., Mollière, P., . . . Wright, G. (2024). SO2, silicate clouds, but no CH4 detected in a warm Neptune. Nature, 625, 51-54
Open this publication in new window or tab >>SO2, silicate clouds, but no CH4 detected in a warm Neptune
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2024 (English)In: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 625, p. 51-54Article in journal (Refereed) Published
Abstract [en]

WASP-107b is a warm (approximately 740 K) transiting planet with a Neptune-like mass of roughly 30.5 M and Jupiter-like radius of about 0.94 RJ (refs. 1,2), whose extended atmosphere is eroding3. Previous observations showed evidence for water vapour and a thick, high-altitude condensate layer in the atmosphere of WASP-107b (refs. 4,5). Recently, photochemically produced sulfur dioxide (SO2) was detected in the atmosphere of a hot (about 1,200 K) Saturn-mass planet from transmission spectroscopy near 4.05 μm (refs. 6,7), but for temperatures below about 1,000 K, sulfur is predicted to preferably form sulfur allotropes instead of SO2 (refs. 8,9,10). Here we report the 9σ detection of two fundamental vibration bands of SO2, at 7.35 μm and 8.69 μm, in the transmission spectrum of WASP-107b using the Mid-Infrared Instrument (MIRI) of JWST. This discovery establishes WASP-107b as the second irradiated exoplanet with confirmed photochemistry, extending the temperature range of exoplanets exhibiting detected photochemistry from about 1,200 K down to about 740 K. Furthermore, our spectral analysis reveals the presence of silicate clouds, which are strongly favoured (around 7σ) over simpler cloud set-ups. Furthermore, water is detected (around 12σ) but methane is not. These findings provide evidence of disequilibrium chemistry and indicate a dynamically active atmosphere with a super-solar metallicity.

National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:su:diva-227413 (URN)10.1038/s41586-023-06849-0 (DOI)001170657600001 ()37967578 (PubMedID)2-s2.0-85180250085 (Scopus ID)
Available from: 2024-03-14 Created: 2024-03-14 Last updated: 2024-04-29Bibliographically approved
Swayne, M. I., Olofsson, G., Brandeker, A. & Wilson, T. G. (2024). The EBLM Project- XI. Mass, radius, and effective temperature measurements for 23 M-dwarf companions to solar-type stars observed with CHEOPS. Monthly notices of the Royal Astronomical Society, 528(4), 5703-5722
Open this publication in new window or tab >>The EBLM Project- XI. Mass, radius, and effective temperature measurements for 23 M-dwarf companions to solar-type stars observed with CHEOPS
2024 (English)In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 528, no 4, p. 5703-5722Article in journal (Refereed) Published
Abstract [en]

Observations of low-mass stars have frequently shown a disagreement between observed stellar radii and radii predicted by theoretical stellar structure models. This 'radius inflation' problem could have an impact on both stellar and exoplanetary science. We present the final results of our observation programme with the CHaracterising ExOPlanet Satellite (CHEOPS) to obtain high-precision light curves of eclipsing binaries with low-mass stellar companions (EBLMs). Combined with the spectroscopic orbits of the solar-type companions, we can derive the masses, radii, and effective temperatures of 23 M-dwarf stars. We use the pycheops data analysis software to analyse their primary and secondary occultations. For all but one target, we also perform analyses with Transiting Exoplanet Survey Satellite (TESS) light curves for comparison. We have assessed the impact of starspot-induced variation on our derived parameters and account for this in our radius and effective temperature uncertainties using simulated light curves. We observe trends in inflation with both metallicity and orbital separation. We also observe a strong trend in the difference between theoretical and observational effective temperatures with metallicity. There is no such trend with orbital separation. These results are not consistent with the idea that the observed inflation in stellar radius combines with lower effective temperature to preserve the luminosity predicted by low-mass stellar models. Our EBLM systems provide high-quality and homogeneous measurements that can be used in further studies of radius inflation.

Keywords
techniques: photometric, techniques: spectroscopic, binaries: eclipsing, stars: fundamental parameters, stars: low-mass
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:su:diva-227979 (URN)10.1093/mnras/stad3866 (DOI)001164781800001 ()2-s2.0-85180478235 (Scopus ID)
Available from: 2024-04-05 Created: 2024-04-05 Last updated: 2024-04-05Bibliographically approved
Barrado, D., Mollière, P., Patapis, P., Min, M., Tremblin, P., Ardevol Martinez, F., . . . Wright, G. (2023). 15NH3 in the atmosphere of a cool brown dwarf. Nature, 624(7991), 263-266
Open this publication in new window or tab >>15NH3 in the atmosphere of a cool brown dwarf
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2023 (English)In: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 624, no 7991, p. 263-266Article in journal (Refereed) Published
Abstract [en]

Brown dwarfs serve as ideal laboratories for studying the atmospheres of giant exoplanets on wide orbits, as the governing physical and chemical processes within them are nearly identical. Understanding the formation of gas-giant planets is challenging, often involving the endeavour to link atmospheric abundance ratios, such as the carbon-to-oxygen (C/O) ratio, to formation scenarios. However, the complexity of planet formation requires further tracers, as the unambiguous interpretation of the measured C/O ratio is fraught with complexity. Isotope ratios, such as deuterium to hydrogen and 14N/15N, offer a promising avenue to gain further insight into this formation process, mirroring their use within the Solar System. For exoplanets, only a handful of constraints on 12C/13C exist, pointing to the accretion of 13C-rich ice from beyond the CO iceline of the disks. Here we report on the mid-infrared detection of the 14NH3 and 15NH3 isotopologues in the atmosphere of a cool brown dwarf with an effective temperature of 380 K in a spectrum taken with the Mid-Infrared Instrument (MIRI) of JWST. As expected, our results reveal a 14N/15N value consistent with star-like formation by gravitational collapse, demonstrating that this ratio can be accurately constrained. Because young stars and their planets should be more strongly enriched in the 15N isotope, we expect that 15NH3 will be detectable in several cold, wide-separation exoplanets. 

National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:su:diva-227683 (URN)10.1038/s41586-023-06813-y (DOI)001183169600001 ()37931645 (PubMedID)2-s2.0-85178873849 (Scopus ID)
Available from: 2024-04-05 Created: 2024-04-05 Last updated: 2024-04-05Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-3747-7120

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