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Extremely Irradiated Hot Jupiters: Non-oxide Inversions, H− Opacity, and Thermal Dissociation of Molecules
- Source :
- The Astrophysical Journal. 866:27
- Publication Year :
- 2018
- Publisher :
- American Astronomical Society, 2018.
-
Abstract
- Extremely irradiated hot Jupiters, exoplanets reaching dayside temperatures ${>}$2000 K, stretch our understanding of planetary atmospheres and the models we use to interpret observations. While these objects are planets in every other sense, their atmospheres reach temperatures at low pressures comparable only to stellar atmospheres. In order to understand our \textit{a priori} theoretical expectations for the nature of these objects, we self-consistently model a number of extreme hot Jupiter scenarios with the PHOENIX model atmosphere code. PHOENIX is well-tested on objects from cool brown dwarfs to expanding supernovae shells and its expansive opacity database from the UV to far-IR make PHOENIX well-suited for understanding extremely irradiated hot Jupiters. We find several fundamental differences between hot Jupiters at temperatures ${>}$2500 K and their cooler counterparts. First, absorption by atomic metals like Fe and Mg, molecules including SiO and metal hydrides, and continuous opacity sources like H$^-$ all combined with the short-wavelength output of early-type host stars result in strong thermal inversions, without the need for TiO or VO. Second, many molecular species, including H$_2$O, TiO, and VO are thermally dissociated at pressures probed by eclipse observations, biasing retrieval algorithms that assume uniform vertical abundances. We discuss other interesting properties of these objects, as well as future prospects and predictions for observing and characterizing this unique class of astrophysical object, including the first self-consistent model of the hottest known jovian planet, KELT-9b.<br />23 pages, 16 figures, 1 table. Submitted to ApJ
- Subjects :
- ComputerSystemsOrganization_COMPUTERSYSTEMIMPLEMENTATION
010504 meteorology & atmospheric sciences
Opacity
Oxide
FOS: Physical sciences
ComputerApplications_COMPUTERSINOTHERSYSTEMS
Astrophysics::Cosmology and Extragalactic Astrophysics
Astrophysics
Computer Science::Digital Libraries
01 natural sciences
chemistry.chemical_compound
Spitzer Space Telescope
0103 physical sciences
Hot Jupiter
Astrophysics::Solar and Stellar Astrophysics
Molecule
Irradiation
010303 astronomy & astrophysics
Astrophysics::Galaxy Astrophysics
0105 earth and related environmental sciences
Earth and Planetary Astrophysics (astro-ph.EP)
Physics
Astrophysics::Instrumentation and Methods for Astrophysics
Astronomy and Astrophysics
chemistry
Space and Planetary Science
Thermal dissociation
Astrophysics::Earth and Planetary Astrophysics
Astrophysics - Earth and Planetary Astrophysics
Subjects
Details
- ISSN :
- 15384357
- Volume :
- 866
- Database :
- OpenAIRE
- Journal :
- The Astrophysical Journal
- Accession number :
- edsair.doi.dedup.....aba08764dbbd40a18757354c55a50015
- Full Text :
- https://doi.org/10.3847/1538-4357/aadd9e