Removal of Hot Saturns in Mass–Radius Plane by Runaway Mass Loss
The hot Saturn population exhibits a boundary in mass–radius space, such that no planets are observed at a density less than ∼0.1 g cm ^−3 . Yet, planet interior structure models can readily construct such objects as the natural result of radius inflation. Here, we investigate the role X-ray and ext...
| 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 Letters |
| Subjects: | |
| Online Access: | https://doi.org/10.3847/2041-8213/acbd35 |
| _version_ | 1827827824447193088 |
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| author | Daniel P. Thorngren Eve J. Lee Eric D. Lopez |
| author_facet | Daniel P. Thorngren Eve J. Lee Eric D. Lopez |
| author_sort | Daniel P. Thorngren |
| collection | DOAJ |
| description | The hot Saturn population exhibits a boundary in mass–radius space, such that no planets are observed at a density less than ∼0.1 g cm ^−3 . Yet, planet interior structure models can readily construct such objects as the natural result of radius inflation. Here, we investigate the role X-ray and extreme UV irradiation (XUV)-driven mass loss plays in sculpting the density boundary by constructing interior structure models that include radius inflation, photoevaporative mass loss, and a simple prescription of Roche lobe overflow. We demonstrate that planets puffier than ∼0.1 g cm ^−3 experience a runaway mass loss caused by adiabatic radius expansion as the gas layer is stripped away, providing a good explanation of the observed edge in mass–radius space. The process is also visible in the radius–period and mass–period spaces, though smaller, high-bulk-metallicity planets can still survive at short periods, preserving a partial record of the population distribution at formation. |
| first_indexed | 2024-03-12T03:36:59Z |
| format | Article |
| id | doaj.art-adfa61e07f964832932078c6ffeb79e1 |
| institution | Directory Open Access Journal |
| issn | 2041-8205 |
| language | English |
| last_indexed | 2024-03-12T03:36:59Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal Letters |
| spelling | doaj.art-adfa61e07f964832932078c6ffeb79e12023-09-03T13:08:52ZengIOP PublishingThe Astrophysical Journal Letters2041-82052023-01-019452L3610.3847/2041-8213/acbd35Removal of Hot Saturns in Mass–Radius Plane by Runaway Mass LossDaniel P. Thorngren0https://orcid.org/0000-0002-5113-8558Eve J. Lee1https://orcid.org/0000-0002-1228-9820Eric D. Lopez2https://orcid.org/0000-0002-7727-4603Trottier Institute for Research on Exoplanets (iREx), Université de Montréal , Quebec, Canada ; dpthorngren@gmail.com; Department of Physics & Astronomy, Johns Hopkins University , Baltimore, MD, USADepartment of Physics and Trottier Space Institute, McGill University , Montréal, Québec, H3A 2T8, Canada; Institute for Research on Exoplanets (iREx), Université de Montréal , Quebec, CanadaNASA Goddard Space Flight Center , 8800 Greenbelt Rd., Greenbelt, MD 20771, USA; GSFC Sellers Exoplanet Environments Collaboration, MD, USAThe hot Saturn population exhibits a boundary in mass–radius space, such that no planets are observed at a density less than ∼0.1 g cm ^−3 . Yet, planet interior structure models can readily construct such objects as the natural result of radius inflation. Here, we investigate the role X-ray and extreme UV irradiation (XUV)-driven mass loss plays in sculpting the density boundary by constructing interior structure models that include radius inflation, photoevaporative mass loss, and a simple prescription of Roche lobe overflow. We demonstrate that planets puffier than ∼0.1 g cm ^−3 experience a runaway mass loss caused by adiabatic radius expansion as the gas layer is stripped away, providing a good explanation of the observed edge in mass–radius space. The process is also visible in the radius–period and mass–period spaces, though smaller, high-bulk-metallicity planets can still survive at short periods, preserving a partial record of the population distribution at formation.https://doi.org/10.3847/2041-8213/acbd35Exoplanet evolutionExoplanet structureExoplanetsHot JupitersHot Neptunes |
| spellingShingle | Daniel P. Thorngren Eve J. Lee Eric D. Lopez Removal of Hot Saturns in Mass–Radius Plane by Runaway Mass Loss The Astrophysical Journal Letters Exoplanet evolution Exoplanet structure Exoplanets Hot Jupiters Hot Neptunes |
| title | Removal of Hot Saturns in Mass–Radius Plane by Runaway Mass Loss |
| title_full | Removal of Hot Saturns in Mass–Radius Plane by Runaway Mass Loss |
| title_fullStr | Removal of Hot Saturns in Mass–Radius Plane by Runaway Mass Loss |
| title_full_unstemmed | Removal of Hot Saturns in Mass–Radius Plane by Runaway Mass Loss |
| title_short | Removal of Hot Saturns in Mass–Radius Plane by Runaway Mass Loss |
| title_sort | removal of hot saturns in mass radius plane by runaway mass loss |
| topic | Exoplanet evolution Exoplanet structure Exoplanets Hot Jupiters Hot Neptunes |
| url | https://doi.org/10.3847/2041-8213/acbd35 |
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