The Transient Outgassed Atmosphere of 55 Cancri e
The enigmatic nature of 55 Cancri e has defied theoretical explanation. Any explanation needs to account for the observed variability of its secondary eclipse depth, which is at times consistent with zero in the visible/optical range of wavelengths—a phenomenon that does not occur with its als...
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IOP Publishing
2023-01-01
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| Series: | The Astrophysical Journal Letters |
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| Online Access: | https://doi.org/10.3847/2041-8213/acfe05 |
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| author | Kevin Heng |
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| description | The enigmatic nature of 55 Cancri e has defied theoretical explanation. Any explanation needs to account for the observed variability of its secondary eclipse depth, which is at times consistent with zero in the visible/optical range of wavelengths—a phenomenon that does not occur with its also variable infrared eclipses. Yet despite this variability, its transit depth remains somewhat constant in time and is inconsistent with opaque material filling its Hill sphere. The current study explores the possibility of a thin, transient, secondary atmosphere on 55 Cancri e that is sourced by geochemical outgassing. Its transient nature derives from the inability of outgassing to be balanced by atmospheric escape. As the outgassed atmosphere escapes and is replenished, it rapidly adjusts to radiative equilibrium and the temperature fluctuations cause the infrared eclipse depths to vary. Atmospheres of pure carbon dioxide or carbon monoxide produce sufficient Rayleigh scattering to explain the observed optical/visible eclipse depths, which vanish in the absence of an atmosphere and the presence of a dark rocky surface. Atmospheres of pure methane are ruled out, because they produce insufficient Rayleigh scattering. Upcoming observations by the James Webb Space Telescope will potentially allow the atmospheric temperature and surface pressure, as well as the surface temperature, to be measured. |
| format | Article |
| id | doaj-art-11112e192fad446eaaa56a8cb4ebfdf7 |
| institution | DOAJ |
| issn | 2041-8205 |
| language | English |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
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| series | The Astrophysical Journal Letters |
| spelling | doaj-art-11112e192fad446eaaa56a8cb4ebfdf72025-08-20T02:55:49ZengIOP PublishingThe Astrophysical Journal Letters2041-82052023-01-019561L2010.3847/2041-8213/acfe05The Transient Outgassed Atmosphere of 55 Cancri eKevin Heng0https://orcid.org/0000-0003-1907-5910Faculty of Physics, Ludwig Maximilian University , Scheinerstrasse 1, D-81679, Munich, Bavaria, Germany ; Kevin.Heng@physik.lmu.de; ARTORG Center for Biomedical Engineering Research, University of Bern , Murtenstrasse 50, CH-3008, Bern, Switzerland; Astronomy & Astrophysics Group, Department of Physics, University of Warwick , Coventry CV4 7AL, UKThe enigmatic nature of 55 Cancri e has defied theoretical explanation. Any explanation needs to account for the observed variability of its secondary eclipse depth, which is at times consistent with zero in the visible/optical range of wavelengths—a phenomenon that does not occur with its also variable infrared eclipses. Yet despite this variability, its transit depth remains somewhat constant in time and is inconsistent with opaque material filling its Hill sphere. The current study explores the possibility of a thin, transient, secondary atmosphere on 55 Cancri e that is sourced by geochemical outgassing. Its transient nature derives from the inability of outgassing to be balanced by atmospheric escape. As the outgassed atmosphere escapes and is replenished, it rapidly adjusts to radiative equilibrium and the temperature fluctuations cause the infrared eclipse depths to vary. Atmospheres of pure carbon dioxide or carbon monoxide produce sufficient Rayleigh scattering to explain the observed optical/visible eclipse depths, which vanish in the absence of an atmosphere and the presence of a dark rocky surface. Atmospheres of pure methane are ruled out, because they produce insufficient Rayleigh scattering. Upcoming observations by the James Webb Space Telescope will potentially allow the atmospheric temperature and surface pressure, as well as the surface temperature, to be measured.https://doi.org/10.3847/2041-8213/acfe05Exoplanets |
| spellingShingle | Kevin Heng The Transient Outgassed Atmosphere of 55 Cancri e The Astrophysical Journal Letters Exoplanets |
| title | The Transient Outgassed Atmosphere of 55 Cancri e |
| title_full | The Transient Outgassed Atmosphere of 55 Cancri e |
| title_fullStr | The Transient Outgassed Atmosphere of 55 Cancri e |
| title_full_unstemmed | The Transient Outgassed Atmosphere of 55 Cancri e |
| title_short | The Transient Outgassed Atmosphere of 55 Cancri e |
| title_sort | transient outgassed atmosphere of 55 cancri e |
| topic | Exoplanets |
| url | https://doi.org/10.3847/2041-8213/acfe05 |
| work_keys_str_mv | AT kevinheng thetransientoutgassedatmosphereof55cancrie AT kevinheng transientoutgassedatmosphereof55cancrie |