{"title":"The Transient Outgassed Atmosphere of 55 Cancri e","authors":"Kevin Heng","doi":"10.3847/2041-8213/acfe05","DOIUrl":null,"url":null,"abstract":"Abstract 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.","PeriodicalId":55567,"journal":{"name":"Astrophysical Journal Letters","volume":"12 1","pages":"0"},"PeriodicalIF":8.8000,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Astrophysical Journal Letters","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.3847/2041-8213/acfe05","RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ASTRONOMY & ASTROPHYSICS","Score":null,"Total":0}
引用次数: 0
Abstract
Abstract 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.
期刊介绍:
The Astrophysical Journal Letters (ApJL) is widely regarded as the foremost journal for swiftly disseminating groundbreaking astronomical research. It focuses on concise reports that highlight pivotal advancements in the field of astrophysics. By prioritizing timeliness and the generation of immediate interest among researchers, ApJL showcases articles featuring novel discoveries and critical findings that have a profound effect on the scientific community. Moreover, ApJL ensures that published articles are comprehensive in their scope, presenting context that can be readily comprehensible to scientists who may not possess expertise in the specific disciplines covered.