Detectability of Emission from Exoplanet Outflows Calculated by pyTPCI, a New 1D Radiation-hydrodynamic Code

Photoevaporation in exoplanet atmospheres is thought to contribute to the shaping of the small planet radius valley. Escaping atmospheres have been detected in transmission across a variety of exoplanet types, from hot Jupiters to mini-Neptunes. However, no work has yet considered whether outflows m...

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Main Authors: Riley Rosener, Michael Zhang, Jacob L. Bean
Format: Article
Language:English
Published: IOP Publishing 2025-01-01
Series:The Astrophysical Journal
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Online Access:https://doi.org/10.3847/1538-4357/ada6ab
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author Riley Rosener
Michael Zhang
Jacob L. Bean
author_facet Riley Rosener
Michael Zhang
Jacob L. Bean
author_sort Riley Rosener
collection DOAJ
description Photoevaporation in exoplanet atmospheres is thought to contribute to the shaping of the small planet radius valley. Escaping atmospheres have been detected in transmission across a variety of exoplanet types, from hot Jupiters to mini-Neptunes. However, no work has yet considered whether outflows might also be detectable in emission. We introduce pyTPCI, a new, open-source self-consistent 1D radiative-hydrodynamics code that is an improved version of The PLUTO-CLOUDY Interface. We use pyTPCI to model seven exoplanets (HD 189733b, HD 209458b, WASP-69b, WASP-107b, TOI-1430b, TOI-560b, and HAT-P-32b) at varying metallicities and compute their emission spectra to investigate their detectability across a variety of spectral lines. We calculate the eclipse depths and signal-to-noise ratios (SNRs) of these lines for a 10 m class telescope with a high-resolution spectrograph, taking into account appropriate line broadening mechanisms. We show that the most detectable spectral lines tend to be the 589 nm Na i doublet and the 1083 nm metastable helium triplet. H α and Mg i 457 nm are moderately strong for some planets at some metallicities, but they are almost always optically thin, so some of their emission may not be from the outflow. The planet with the highest-flux, highest-eclipse-depth, and highest-SNR lines is HD 189733b, with a Na i eclipse depth of 410 ppm and SNR of 2.4 per eclipse, and a He* eclipse depth of 170 ppm and SNR of 1.3. These signals would be marginally detectable with Keck if 3–10 eclipses were observed, assuming (over optimistically) photon limited observations.
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spelling doaj-art-05d9b1fadf6a4fef91cc8e096f9b7dbc2025-02-03T13:55:44ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-0198013410.3847/1538-4357/ada6abDetectability of Emission from Exoplanet Outflows Calculated by pyTPCI, a New 1D Radiation-hydrodynamic CodeRiley Rosener0https://orcid.org/0000-0001-7905-2134Michael Zhang1https://orcid.org/0000-0002-0659-1783Jacob L. Bean2https://orcid.org/0000-0003-4733-6532Department of Astronomy & Astrophysics, University of Chicago , 5640 S Ellis Avenue, Chicago, IL 60637, USA ; rosener.riley@gmail.comDepartment of Astronomy & Astrophysics, University of Chicago , 5640 S Ellis Avenue, Chicago, IL 60637, USA ; rosener.riley@gmail.comDepartment of Astronomy & Astrophysics, University of Chicago , 5640 S Ellis Avenue, Chicago, IL 60637, USA ; rosener.riley@gmail.comPhotoevaporation in exoplanet atmospheres is thought to contribute to the shaping of the small planet radius valley. Escaping atmospheres have been detected in transmission across a variety of exoplanet types, from hot Jupiters to mini-Neptunes. However, no work has yet considered whether outflows might also be detectable in emission. We introduce pyTPCI, a new, open-source self-consistent 1D radiative-hydrodynamics code that is an improved version of The PLUTO-CLOUDY Interface. We use pyTPCI to model seven exoplanets (HD 189733b, HD 209458b, WASP-69b, WASP-107b, TOI-1430b, TOI-560b, and HAT-P-32b) at varying metallicities and compute their emission spectra to investigate their detectability across a variety of spectral lines. We calculate the eclipse depths and signal-to-noise ratios (SNRs) of these lines for a 10 m class telescope with a high-resolution spectrograph, taking into account appropriate line broadening mechanisms. We show that the most detectable spectral lines tend to be the 589 nm Na i doublet and the 1083 nm metastable helium triplet. H α and Mg i 457 nm are moderately strong for some planets at some metallicities, but they are almost always optically thin, so some of their emission may not be from the outflow. The planet with the highest-flux, highest-eclipse-depth, and highest-SNR lines is HD 189733b, with a Na i eclipse depth of 410 ppm and SNR of 2.4 per eclipse, and a He* eclipse depth of 170 ppm and SNR of 1.3. These signals would be marginally detectable with Keck if 3–10 eclipses were observed, assuming (over optimistically) photon limited observations.https://doi.org/10.3847/1538-4357/ada6abExoplanet atmospheresHydrodynamical simulationsRadiative transfer simulationsExtrasolar gaseous giant planetsMini Neptunes
spellingShingle Riley Rosener
Michael Zhang
Jacob L. Bean
Detectability of Emission from Exoplanet Outflows Calculated by pyTPCI, a New 1D Radiation-hydrodynamic Code
The Astrophysical Journal
Exoplanet atmospheres
Hydrodynamical simulations
Radiative transfer simulations
Extrasolar gaseous giant planets
Mini Neptunes
title Detectability of Emission from Exoplanet Outflows Calculated by pyTPCI, a New 1D Radiation-hydrodynamic Code
title_full Detectability of Emission from Exoplanet Outflows Calculated by pyTPCI, a New 1D Radiation-hydrodynamic Code
title_fullStr Detectability of Emission from Exoplanet Outflows Calculated by pyTPCI, a New 1D Radiation-hydrodynamic Code
title_full_unstemmed Detectability of Emission from Exoplanet Outflows Calculated by pyTPCI, a New 1D Radiation-hydrodynamic Code
title_short Detectability of Emission from Exoplanet Outflows Calculated by pyTPCI, a New 1D Radiation-hydrodynamic Code
title_sort detectability of emission from exoplanet outflows calculated by pytpci a new 1d radiation hydrodynamic code
topic Exoplanet atmospheres
Hydrodynamical simulations
Radiative transfer simulations
Extrasolar gaseous giant planets
Mini Neptunes
url https://doi.org/10.3847/1538-4357/ada6ab
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