Overcast Mornings and Clear Evenings in Hot Jupiter Exoplanet Atmospheres
Aerosols are an old topic in the young field of exoplanet atmospheres. Understanding what they are, how they form, and where they go has long provided a fertile playground for theorists. For observers, however, aerosols have been a multidecade migraine, as their chronic presence hides atmospheric fe...
Saved in:
| Main Authors: | , , , , , , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2025-01-01
|
| Series: | The Astrophysical Journal Letters |
| Subjects: | |
| Online Access: | https://doi.org/10.3847/2041-8213/adf20f |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1849393556113850368 |
|---|---|
| author | Guangwei Fu Sagnick Mukherjee Kevin B. Stevenson David K. Sing Reza Ashtari Nathan Mayne Joshua D. Lothringer Maria Zamyatina Stephen P. Schmidt Carlos Gascón Natalie H. Allen Katherine A. Bennett Mercedes López-Morales |
| author_facet | Guangwei Fu Sagnick Mukherjee Kevin B. Stevenson David K. Sing Reza Ashtari Nathan Mayne Joshua D. Lothringer Maria Zamyatina Stephen P. Schmidt Carlos Gascón Natalie H. Allen Katherine A. Bennett Mercedes López-Morales |
| author_sort | Guangwei Fu |
| collection | DOAJ |
| description | Aerosols are an old topic in the young field of exoplanet atmospheres. Understanding what they are, how they form, and where they go has long provided a fertile playground for theorists. For observers, however, aerosols have been a multidecade migraine, as their chronic presence hides atmospheric features. For hot Jupiters, the large day–night temperature contrast drives inhomogeneous thermal structures and aerosol distribution, leading to different limb properties probed by transit spectra. We present JWST NIRISS/SOSS spectra of morning and evening limbs for nine gas giants with equilibrium temperatures of ∼800–1700 K. By measuring feature size of the 1.4 μ m water band for both limbs, we found three planets (WASP-39 b, WASP-94 Ab, and WASP-17 b) show prominent (>5 σ ) limb–limb atmospheric opacity difference with muted morning and clear evening limbs. The heavily muted water features on morning limbs indicate high-altitude (0.1–0.01 mbar) aerosols. To simultaneously have clear evening limbs requires processes with timescales (∼day) comparable to advection to remove these lofted grains, and we found that both downwelling flow and dayside cloud evaporation could be plausible mechanisms. We hypothesize an empirical boundary—termed the “asymmetry horizon”—in temperature–gravity space that marks the transition where inhomogeneous aerosol coverage begins to emerge. Heterogeneous aerosol coverage is common among hot Jupiters. If unrecognized, limb averaging suppresses spectral features, mimicking high-mean-molecular-weight atmospheres, inflating inferred metallicity by up to 2 dex, and underestimating limb temperatures by as much as half. Finally, we introduce the Limb Spectroscopy Metric to predict limb spectral feature size based on planet parameters. |
| format | Article |
| id | doaj-art-e335e922d4ae438ba8389d2ce857249e |
| institution | Kabale University |
| issn | 2041-8205 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal Letters |
| spelling | doaj-art-e335e922d4ae438ba8389d2ce857249e2025-08-20T03:40:22ZengIOP PublishingThe Astrophysical Journal Letters2041-82052025-01-019891L1710.3847/2041-8213/adf20fOvercast Mornings and Clear Evenings in Hot Jupiter Exoplanet AtmospheresGuangwei Fu0https://orcid.org/0000-0002-3263-2251Sagnick Mukherjee1https://orcid.org/0000-0003-1622-1302Kevin B. Stevenson2https://orcid.org/0000-0002-7352-7941David K. Sing3https://orcid.org/0000-0001-6050-7645Reza Ashtari4https://orcid.org/0000-0001-8943-9148Nathan Mayne5https://orcid.org/0000-0001-6707-4563Joshua D. Lothringer6https://orcid.org/0000-0003-3667-8633Maria Zamyatina7https://orcid.org/0000-0002-9705-0535Stephen P. Schmidt8https://orcid.org/0000-0001-8510-7365Carlos Gascón9https://orcid.org/0000-0001-5097-9251Natalie H. Allen10https://orcid.org/0000-0002-0832-710XKatherine A. Bennett11https://orcid.org/0000-0002-9030-0132Mercedes López-Morales12https://orcid.org/0000-0003-3204-8183Department of Physics and Astronomy, Johns Hopkins University , Baltimore, MD, USADepartment of Physics and Astronomy, Johns Hopkins University , Baltimore, MD, USA; Department of Astronomy and Astrophysics, University of California , Santa Cruz, CA 95064, USAJHU Applied Physics Laboratory , 11100 Johns Hopkins Road, Laurel, MD 20723, USADepartment of Physics and Astronomy, Johns Hopkins University , Baltimore, MD, USAJHU Applied Physics Laboratory , 11100 Johns Hopkins Road, Laurel, MD 20723, USADepartment of Physics and Astronomy, Faculty of Environment Science and Economy, University of Exeter , EX4 4QL, UKSpace Telescope Science Institute , Baltimore, MD, USADepartment of Physics and Astronomy, Faculty of Environment Science and Economy, University of Exeter , EX4 4QL, UKDepartment of Physics and Astronomy, Johns Hopkins University , Baltimore, MD, USACenter for Astrophysics, Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USA; Institut d’Estudis Espacials de Catalunya (IEEC) , 08860 Castelldefels, Barcelona, SpainDepartment of Physics and Astronomy, Johns Hopkins University , Baltimore, MD, USADepartment of Earth and Planetary Sciences, Johns Hopkins University , Baltimore, MD, USASpace Telescope Science Institute , Baltimore, MD, USA; Center for Astrophysics, Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USAAerosols are an old topic in the young field of exoplanet atmospheres. Understanding what they are, how they form, and where they go has long provided a fertile playground for theorists. For observers, however, aerosols have been a multidecade migraine, as their chronic presence hides atmospheric features. For hot Jupiters, the large day–night temperature contrast drives inhomogeneous thermal structures and aerosol distribution, leading to different limb properties probed by transit spectra. We present JWST NIRISS/SOSS spectra of morning and evening limbs for nine gas giants with equilibrium temperatures of ∼800–1700 K. By measuring feature size of the 1.4 μ m water band for both limbs, we found three planets (WASP-39 b, WASP-94 Ab, and WASP-17 b) show prominent (>5 σ ) limb–limb atmospheric opacity difference with muted morning and clear evening limbs. The heavily muted water features on morning limbs indicate high-altitude (0.1–0.01 mbar) aerosols. To simultaneously have clear evening limbs requires processes with timescales (∼day) comparable to advection to remove these lofted grains, and we found that both downwelling flow and dayside cloud evaporation could be plausible mechanisms. We hypothesize an empirical boundary—termed the “asymmetry horizon”—in temperature–gravity space that marks the transition where inhomogeneous aerosol coverage begins to emerge. Heterogeneous aerosol coverage is common among hot Jupiters. If unrecognized, limb averaging suppresses spectral features, mimicking high-mean-molecular-weight atmospheres, inflating inferred metallicity by up to 2 dex, and underestimating limb temperatures by as much as half. Finally, we introduce the Limb Spectroscopy Metric to predict limb spectral feature size based on planet parameters.https://doi.org/10.3847/2041-8213/adf20fExoplanet atmospheresExoplanet atmospheric composition |
| spellingShingle | Guangwei Fu Sagnick Mukherjee Kevin B. Stevenson David K. Sing Reza Ashtari Nathan Mayne Joshua D. Lothringer Maria Zamyatina Stephen P. Schmidt Carlos Gascón Natalie H. Allen Katherine A. Bennett Mercedes López-Morales Overcast Mornings and Clear Evenings in Hot Jupiter Exoplanet Atmospheres The Astrophysical Journal Letters Exoplanet atmospheres Exoplanet atmospheric composition |
| title | Overcast Mornings and Clear Evenings in Hot Jupiter Exoplanet Atmospheres |
| title_full | Overcast Mornings and Clear Evenings in Hot Jupiter Exoplanet Atmospheres |
| title_fullStr | Overcast Mornings and Clear Evenings in Hot Jupiter Exoplanet Atmospheres |
| title_full_unstemmed | Overcast Mornings and Clear Evenings in Hot Jupiter Exoplanet Atmospheres |
| title_short | Overcast Mornings and Clear Evenings in Hot Jupiter Exoplanet Atmospheres |
| title_sort | overcast mornings and clear evenings in hot jupiter exoplanet atmospheres |
| topic | Exoplanet atmospheres Exoplanet atmospheric composition |
| url | https://doi.org/10.3847/2041-8213/adf20f |
| work_keys_str_mv | AT guangweifu overcastmorningsandcleareveningsinhotjupiterexoplanetatmospheres AT sagnickmukherjee overcastmorningsandcleareveningsinhotjupiterexoplanetatmospheres AT kevinbstevenson overcastmorningsandcleareveningsinhotjupiterexoplanetatmospheres AT davidksing overcastmorningsandcleareveningsinhotjupiterexoplanetatmospheres AT rezaashtari overcastmorningsandcleareveningsinhotjupiterexoplanetatmospheres AT nathanmayne overcastmorningsandcleareveningsinhotjupiterexoplanetatmospheres AT joshuadlothringer overcastmorningsandcleareveningsinhotjupiterexoplanetatmospheres AT mariazamyatina overcastmorningsandcleareveningsinhotjupiterexoplanetatmospheres AT stephenpschmidt overcastmorningsandcleareveningsinhotjupiterexoplanetatmospheres AT carlosgascon overcastmorningsandcleareveningsinhotjupiterexoplanetatmospheres AT nataliehallen overcastmorningsandcleareveningsinhotjupiterexoplanetatmospheres AT katherineabennett overcastmorningsandcleareveningsinhotjupiterexoplanetatmospheres AT mercedeslopezmorales overcastmorningsandcleareveningsinhotjupiterexoplanetatmospheres |