Publications by authors named "Yamila Miguel"

Characterizing rocky exoplanets is a central aim of astronomy, and yet the search for atmospheres on rocky exoplanets has so far resulted in either tight upper limits on the atmospheric mass or inconclusive results. The 1.95R and 8.

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The recent inference of sulfur dioxide (SO) in the atmosphere of the hot (approximately 1,100 K), Saturn-mass exoplanet WASP-39b from near-infrared JWST observations suggests that photochemistry is a key process in high-temperature exoplanet atmospheres. This is because of the low (<1 ppb) abundance of SO under thermochemical equilibrium compared with that produced from the photochemistry of HO and HS (1-10 ppm). However, the SO inference was made from a single, small molecular feature in the transmission spectrum of WASP-39b at 4.

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Article Synopsis
  • The study discovered a Neptune-mass exoplanet orbiting the low-mass star LHS 3154, which is significantly less massive than the Sun.
  • The exoplanet has a short orbital period of 3.7 days and a minimum mass of 13.2 Earth masses, challenging existing theories of planet formation.
  • Simulations indicate that the high mass ratio between the planet and its star is unexpected, suggesting that close-in Neptune-mass planets would require much more dust in the protoplanetary disk than typically found around such low-mass stars.
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  • Photochemistry plays a critical role in regulating the composition and stability of planetary atmospheres, but clear photochemical products have not been detected in exoplanets until recently.* -
  • The James Webb Space Telescope (JWST) detected sulfur dioxide (SO) in the atmosphere of the exoplanet WASP-39b, suggesting photochemical processes create SO in this gas giant's atmosphere.* -
  • The presence of SO, linked to the oxidation of hydrogen sulfide, indicates WASP-39b has high metallicity (about 10 times that of the sun), and its spectral features could help understand more about similar exoplanets.*
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  • Measuring the metallicity and carbon-to-oxygen (C/O) ratio in exoplanet atmospheres helps to understand their chemical processes and formation history.
  • The James Webb Space Telescope (JWST) allows for advanced observations of exoplanets, notably WASP-39b, providing insights through time-series data with high precision in a new wavelength range.
  • Findings include the detection of water vapor in the atmosphere with a high metallicity (1-100 times that of the Sun) and a low C/O ratio, suggesting the potential for significant solid material accretion during formation or chemical disequilibrium in the atmosphere.
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The Saturn-mass exoplanet WASP-39b has been the subject of extensive efforts to determine its atmospheric properties using transmission spectroscopy. However, these efforts have been hampered by modelling degeneracies between composition and cloud properties that are caused by limited data quality. Here we present the transmission spectrum of WASP-39b obtained using the Single-Object Slitless Spectroscopy (SOSS) mode of the Near Infrared Imager and Slitless Spectrograph (NIRISS) instrument on the JWST.

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Measuring the abundances of carbon and oxygen in exoplanet atmospheres is considered a crucial avenue for unlocking the formation and evolution of exoplanetary systems. Access to the chemical inventory of an exoplanet requires high-precision observations, often inferred from individual molecular detections with low-resolution space-based and high-resolution ground-based facilities. Here we report the medium-resolution (R ≈ 600) transmission spectrum of an exoplanet atmosphere between 3 and 5 μm covering several absorption features for the Saturn-mass exoplanet WASP-39b (ref.

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Phosphine could be a key molecule in the understanding of exotic chemistry that occurs in (exo)planetary atmospheres. While phosphine has been detected in the Solar System's giant planets, it has not been observed in exoplanets to date. In the exoplanetary context, however, it has been theorized to be a potential biosignature molecule.

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The goal of the Ariel space mission is to observe a large and diversified population of transiting planets around a range of host star types to collect information on their atmospheric composition. The planetary bulk and atmospheric compositions bear the marks of the way the planets formed: Ariel's observations will therefore provide an unprecedented wealth of data to advance our understanding of planet formation in our Galaxy. A number of environmental and evolutionary factors, however, can affect the final atmospheric composition.

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Exoplanet science is one of the most thriving fields of modern astrophysics. A major goal is the atmospheric characterization of dozens of small, terrestrial exoplanets in order to search for signatures in their atmospheres that indicate biological activity, assess their ability to provide conditions for life as we know it, and investigate their expected atmospheric diversity. None of the currently adopted projects or missions, from ground or in space, can address these goals.

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