Helium in the Extended Atmosphere of the Warm Superpuff TOI-1420b
Superpuffs are planets with exceptionally low densities ( ρ ≲ 0.1 g cm ^−3 ) and core masses ( M _c ≲ 5 M _⊕ ). Many lower-mass ( M _p ≲ 10 M _⊕ ) superpuffs are expected to be unstable to catastrophic mass loss via photoevaporation and/or boil-off, whereas the larger gravitational potentials of hig...
| Main Authors: | , , , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2024-01-01
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| Series: | The Astronomical Journal |
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| Online Access: | https://doi.org/10.3847/1538-3881/ad3241 |
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| author | Shreyas Vissapragada Michael Greklek-McKeon Dion Linssen Morgan MacLeod Daniel P. Thorngren Peter Gao Heather A. Knutson David W. Latham Mercedes López-Morales Antonija Oklopčić Jorge Pérez González Morgan Saidel Abigail Tumborang Stephanie Yoshida |
| author_facet | Shreyas Vissapragada Michael Greklek-McKeon Dion Linssen Morgan MacLeod Daniel P. Thorngren Peter Gao Heather A. Knutson David W. Latham Mercedes López-Morales Antonija Oklopčić Jorge Pérez González Morgan Saidel Abigail Tumborang Stephanie Yoshida |
| author_sort | Shreyas Vissapragada |
| collection | DOAJ |
| description | Superpuffs are planets with exceptionally low densities ( ρ ≲ 0.1 g cm ^−3 ) and core masses ( M _c ≲ 5 M _⊕ ). Many lower-mass ( M _p ≲ 10 M _⊕ ) superpuffs are expected to be unstable to catastrophic mass loss via photoevaporation and/or boil-off, whereas the larger gravitational potentials of higher-mass ( M _p ≳ 10 M _⊕ ) superpuffs should make them more stable to these processes. We test this expectation by studying atmospheric loss in the warm, higher-mass superpuff TOI-1420b ( M = 25.1 M _⊕ , R = 11.9 R _⊕ , ρ = 0.08 g cm ^−3 , T _eq = 960 K). We observed one full transit and one partial transit of this planet using the metastable helium filter on Palomar/WIRC and found that the helium transits were 0.671% ± 0.079% (8.5 σ ) deeper than the TESS transits, indicating an outflowing atmosphere. We modeled the excess helium absorption using a self-consistent 1D hydrodynamics code to constrain the thermal structure of the outflow given different assumptions for the stellar XUV spectrum. These calculations then informed a 3D simulation, which provided a good match to the observations with a modest planetary mass-loss rate of 10 ^10.82 g s ^−1 ( ${M}_{p}/\dot{M}\approx 70$ Gyr). Superpuffs with M _p ≳ 10 M _⊕ , like TOI-1420b and WASP-107b, appear perfectly capable of retaining atmospheres over long timescales; therefore, these planets may have formed with the unusually large envelope mass fractions they appear to possess today. Alternatively, tidal circularization could have plausibly heated and inflated these planets, which would bring their envelope mass fractions into better agreement with expectations from core-nucleated accretion. |
| first_indexed | 2024-04-24T12:29:59Z |
| format | Article |
| id | doaj.art-befb1ce6c87345458df59c4c423d829f |
| institution | Directory Open Access Journal |
| issn | 1538-3881 |
| language | English |
| last_indexed | 2024-04-24T12:29:59Z |
| publishDate | 2024-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astronomical Journal |
| spelling | doaj.art-befb1ce6c87345458df59c4c423d829f2024-04-08T07:18:00ZengIOP PublishingThe Astronomical Journal1538-38812024-01-01167519910.3847/1538-3881/ad3241Helium in the Extended Atmosphere of the Warm Superpuff TOI-1420bShreyas Vissapragada0https://orcid.org/0000-0003-2527-1475Michael Greklek-McKeon1https://orcid.org/0000-0002-0371-1647Dion Linssen2https://orcid.org/0000-0001-6025-6663Morgan MacLeod3https://orcid.org/0000-0002-1417-8024Daniel P. Thorngren4https://orcid.org/0000-0002-5113-8558Peter Gao5https://orcid.org/0000-0002-8518-9601Heather A. Knutson6https://orcid.org/0000-0002-5375-4725David W. Latham7https://orcid.org/0000-0001-9911-7388Mercedes López-Morales8https://orcid.org/0000-0003-3204-8183Antonija Oklopčić9https://orcid.org/0000-0002-9584-6476Jorge Pérez González10https://orcid.org/0000-0001-7144-589XMorgan Saidel11https://orcid.org/0000-0001-9518-9691Abigail Tumborang12Stephanie Yoshida13https://orcid.org/0000-0003-4015-9975Center for Astrophysics ∣Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USA ; shreyas.vissapragada@cfa.harvard.eduDivision of Geological and Planetary Sciences, California Institute of Technology , 1200 East California Boulevard, Pasadena, CA 91125, USAAnton Pannekoek Institute for Astronomy, University of Amsterdam , Science Park 904, 1098 XH Amsterdam, The NetherlandsCenter for Astrophysics ∣Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USA ; shreyas.vissapragada@cfa.harvard.eduDepartment of Physics & Astronomy, Johns Hopkins University , Baltimore, MD, USAEarth & Planets Laboratory, Carnegie Institution for Science , Washington, DC, USADivision of Geological and Planetary Sciences, California Institute of Technology , 1200 East California Boulevard, Pasadena, CA 91125, USACenter for Astrophysics ∣Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USA ; shreyas.vissapragada@cfa.harvard.eduCenter for Astrophysics ∣Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USA ; shreyas.vissapragada@cfa.harvard.eduAnton Pannekoek Institute for Astronomy, University of Amsterdam , Science Park 904, 1098 XH Amsterdam, The NetherlandsDepartment of Physics & Astronomy, University College London , Gower Street, WC1E 6BT London, UKDivision of Geological and Planetary Sciences, California Institute of Technology , 1200 East California Boulevard, Pasadena, CA 91125, USASchool of Physics and Astronomy, University of St. Andrews , North Haugh, St. Andrews, KY16 9SS, UKCenter for Astrophysics ∣Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USA ; shreyas.vissapragada@cfa.harvard.eduSuperpuffs are planets with exceptionally low densities ( ρ ≲ 0.1 g cm ^−3 ) and core masses ( M _c ≲ 5 M _⊕ ). Many lower-mass ( M _p ≲ 10 M _⊕ ) superpuffs are expected to be unstable to catastrophic mass loss via photoevaporation and/or boil-off, whereas the larger gravitational potentials of higher-mass ( M _p ≳ 10 M _⊕ ) superpuffs should make them more stable to these processes. We test this expectation by studying atmospheric loss in the warm, higher-mass superpuff TOI-1420b ( M = 25.1 M _⊕ , R = 11.9 R _⊕ , ρ = 0.08 g cm ^−3 , T _eq = 960 K). We observed one full transit and one partial transit of this planet using the metastable helium filter on Palomar/WIRC and found that the helium transits were 0.671% ± 0.079% (8.5 σ ) deeper than the TESS transits, indicating an outflowing atmosphere. We modeled the excess helium absorption using a self-consistent 1D hydrodynamics code to constrain the thermal structure of the outflow given different assumptions for the stellar XUV spectrum. These calculations then informed a 3D simulation, which provided a good match to the observations with a modest planetary mass-loss rate of 10 ^10.82 g s ^−1 ( ${M}_{p}/\dot{M}\approx 70$ Gyr). Superpuffs with M _p ≳ 10 M _⊕ , like TOI-1420b and WASP-107b, appear perfectly capable of retaining atmospheres over long timescales; therefore, these planets may have formed with the unusually large envelope mass fractions they appear to possess today. Alternatively, tidal circularization could have plausibly heated and inflated these planets, which would bring their envelope mass fractions into better agreement with expectations from core-nucleated accretion.https://doi.org/10.3847/1538-3881/ad3241Exoplanet astronomyExoplanet atmospheresExoplanet atmospheric evolution |
| spellingShingle | Shreyas Vissapragada Michael Greklek-McKeon Dion Linssen Morgan MacLeod Daniel P. Thorngren Peter Gao Heather A. Knutson David W. Latham Mercedes López-Morales Antonija Oklopčić Jorge Pérez González Morgan Saidel Abigail Tumborang Stephanie Yoshida Helium in the Extended Atmosphere of the Warm Superpuff TOI-1420b The Astronomical Journal Exoplanet astronomy Exoplanet atmospheres Exoplanet atmospheric evolution |
| title | Helium in the Extended Atmosphere of the Warm Superpuff TOI-1420b |
| title_full | Helium in the Extended Atmosphere of the Warm Superpuff TOI-1420b |
| title_fullStr | Helium in the Extended Atmosphere of the Warm Superpuff TOI-1420b |
| title_full_unstemmed | Helium in the Extended Atmosphere of the Warm Superpuff TOI-1420b |
| title_short | Helium in the Extended Atmosphere of the Warm Superpuff TOI-1420b |
| title_sort | helium in the extended atmosphere of the warm superpuff toi 1420b |
| topic | Exoplanet astronomy Exoplanet atmospheres Exoplanet atmospheric evolution |
| url | https://doi.org/10.3847/1538-3881/ad3241 |
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