The Three Regimes of Atmospheric Evaporation for Super-Earths and Sub-Neptunes
A significant fraction of super-Earths and sub-Neptunes are thought to experience an extreme loss of volatiles because of atmospheric evaporation in the early stages of their life. Though the mechanisms behind the extreme mass loss are not fully understood, two contenders have been widely discussed:...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2023-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/ac9d34 |
| _version_ | 1797701445077696512 |
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| author | Darius Modirrousta-Galian Jun Korenaga |
| author_facet | Darius Modirrousta-Galian Jun Korenaga |
| author_sort | Darius Modirrousta-Galian |
| collection | DOAJ |
| description | A significant fraction of super-Earths and sub-Neptunes are thought to experience an extreme loss of volatiles because of atmospheric evaporation in the early stages of their life. Though the mechanisms behind the extreme mass loss are not fully understood, two contenders have been widely discussed: photoevaporation from X-ray and ultraviolet irradiation and core-powered mass loss. Here, it is shown that both mechanisms occur, but with different timescales, and that atmospheric loss can take place over three regimes. In the first regime, a planet has very high internal temperatures arising from its high-energy formation processes. These high temperatures give rise to a fully convecting atmosphere that efficiently loses mass without much internal cooling. The second regime applies to planets with lower internal temperatures, so a radiative region forms, but the photosphere still remains outside the Bondi radius. Hence, mass loss continues to depend only on the internal temperatures. Planets with the lowest internal temperatures are in the third regime, when the photosphere forms below the Bondi radius and mass is lost primarily because of X-ray and ultraviolet irradiation. This paper provides the first unifying framework for modeling atmospheric evaporation through the life span of a planet. |
| first_indexed | 2024-03-12T04:35:45Z |
| format | Article |
| id | doaj.art-2aa9ddcee23048f7b55ac6b4cc6c58b2 |
| institution | Directory Open Access Journal |
| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-03-12T04:35:45Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj.art-2aa9ddcee23048f7b55ac6b4cc6c58b22023-09-03T09:55:22ZengIOP PublishingThe Astrophysical Journal1538-43572023-01-0194311110.3847/1538-4357/ac9d34The Three Regimes of Atmospheric Evaporation for Super-Earths and Sub-NeptunesDarius Modirrousta-Galian0https://orcid.org/0000-0001-6425-9415Jun Korenaga1https://orcid.org/0000-0002-4785-2273Yale University , Department of Earth and Planetary Sciences, 210 Whitney Avenue, New Haven, CT 06511, USA ; darius.modirrousta-galian@yale.eduYale University , Department of Earth and Planetary Sciences, 210 Whitney Avenue, New Haven, CT 06511, USA ; darius.modirrousta-galian@yale.eduA significant fraction of super-Earths and sub-Neptunes are thought to experience an extreme loss of volatiles because of atmospheric evaporation in the early stages of their life. Though the mechanisms behind the extreme mass loss are not fully understood, two contenders have been widely discussed: photoevaporation from X-ray and ultraviolet irradiation and core-powered mass loss. Here, it is shown that both mechanisms occur, but with different timescales, and that atmospheric loss can take place over three regimes. In the first regime, a planet has very high internal temperatures arising from its high-energy formation processes. These high temperatures give rise to a fully convecting atmosphere that efficiently loses mass without much internal cooling. The second regime applies to planets with lower internal temperatures, so a radiative region forms, but the photosphere still remains outside the Bondi radius. Hence, mass loss continues to depend only on the internal temperatures. Planets with the lowest internal temperatures are in the third regime, when the photosphere forms below the Bondi radius and mass is lost primarily because of X-ray and ultraviolet irradiation. This paper provides the first unifying framework for modeling atmospheric evaporation through the life span of a planet.https://doi.org/10.3847/1538-4357/ac9d34Mini NeptunesSuper EarthsStar-planet interactionsExoplanet evolutionExoplanet atmospheresPlanetary interior |
| spellingShingle | Darius Modirrousta-Galian Jun Korenaga The Three Regimes of Atmospheric Evaporation for Super-Earths and Sub-Neptunes The Astrophysical Journal Mini Neptunes Super Earths Star-planet interactions Exoplanet evolution Exoplanet atmospheres Planetary interior |
| title | The Three Regimes of Atmospheric Evaporation for Super-Earths and Sub-Neptunes |
| title_full | The Three Regimes of Atmospheric Evaporation for Super-Earths and Sub-Neptunes |
| title_fullStr | The Three Regimes of Atmospheric Evaporation for Super-Earths and Sub-Neptunes |
| title_full_unstemmed | The Three Regimes of Atmospheric Evaporation for Super-Earths and Sub-Neptunes |
| title_short | The Three Regimes of Atmospheric Evaporation for Super-Earths and Sub-Neptunes |
| title_sort | three regimes of atmospheric evaporation for super earths and sub neptunes |
| topic | Mini Neptunes Super Earths Star-planet interactions Exoplanet evolution Exoplanet atmospheres Planetary interior |
| url | https://doi.org/10.3847/1538-4357/ac9d34 |
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