ABOVE THE CLOUDS: 1-D MODELING OF OBSERVATIONS OF TIDALLY LOCKED EXTRASOLAR WORLDS

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dc.contributor.advisorDeming, L. Drakeen_US
dc.contributor.advisorDomagal-Goldman, Shawn D.en_US
dc.contributor.authorAfrin Badhan, Mahmudaen_US
dc.contributor.departmentAstronomyen_US
dc.contributor.publisherDigital Repository at the University of Marylanden_US
dc.contributor.publisherUniversity of Maryland (College Park, Md.)en_US
dc.date.accessioned2020-02-01T06:34:29Z
dc.date.available2020-02-01T06:34:29Z
dc.date.issued2019en_US
dc.description.abstractUnique and exotic planetary environments give us an opportunity to understand how planetary systems form and evolve over their lifetime, by placing our planetary system in the context of vastly different extrasolar systems. With orbital separations a fraction of the Mercury-Sun distance, these close-in planets provide us with valuable insights regarding interactions between the stellar and planetary atmospheres. Further, observational biases actually allow such planets to be the first to be observed via transit spectroscopy. Observed spectrophotometric signatures from transit measurements can reveal spectrally active species in a planet’s atmosphere. Present observational technologies can also shed light on the atmosphere’s structure and dynamics. Future missions will allow us to constrain these properties with unprecedented accuracy, and are also being designed to observe increasingly smaller, cooler and less extreme planets. The eventual goal, after all, is to identify a world like our own. To interpret the observations with any certainty, however, we must build robust atmospheric models that sufficiently factor both physical and chemical processes expected in those atmospheres. 3-D climate modeling has shown that tidally-locked Earth-like planets, at the inner edge of M dwarf habitable zones, may retain water-vapor-rich stratospheres. However, flaring M dwarfs have strong UV activity, which may photodisassociate H2O. Using synthetical stellar UV within a 1-D photochemical model, I assess whether water vapor loss driven by high stellar UV would affect its detectability in JWST/MIRI transmission spectroscopy. I pseudo-couple a 3-D climate model to our 1-D model to achieve this. In a follow-up study, I also compute 125 additional atmospheric states by varying the Earth-like planet’s orbital distance (thus moistness) and methane production rates. I check for and quantify the simultaneous presence of detectable ozone and methane in an otherwise abiotic anoxic atmosphere. I have also implemented techniques to robustly quantify atmospheric properties of hot Jupiters from data-driven retrievals and built a versatile template for hot Jupiter atmospheres within our 1-D photochemical modeling tool, which was previously only valid for cool rocky worlds. I sketch out a plan for using this work towards mapping non-equilibrated (non-LTE) emissions from methane in the upper atmospheres of observable giants.en_US
dc.identifierhttps://doi.org/10.13016/z0ek-ut4c
dc.identifier.urihttp://hdl.handle.net/1903/25391
dc.language.isoenen_US
dc.subject.pqcontrolledAstronomyen_US
dc.subject.pqcontrolledAtmospheric sciencesen_US
dc.subject.pqcontrolledAstrophysicsen_US
dc.subject.pquncontrolledplanets and satellites: atmospheresen_US
dc.subject.pquncontrolledplanets and satellites: compositionen_US
dc.subject.pquncontrolledplanets and satellites: giant planetsen_US
dc.subject.pquncontrolledplanets and satellites: terrestrial planetsen_US
dc.subject.pquncontrolledstars: activityen_US
dc.subject.pquncontrolledstars: low-massen_US
dc.titleABOVE THE CLOUDS: 1-D MODELING OF OBSERVATIONS OF TIDALLY LOCKED EXTRASOLAR WORLDSen_US
dc.typeDissertationen_US

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