The imprint of exoplanet formation history on observable present-day spectra of hot Jupiters

Mordasini, Christoph; van Boekel, R.; Mollière, P.; Henning, Th.; Benneke, Björn (2016). The imprint of exoplanet formation history on observable present-day spectra of hot Jupiters. Astrophysical journal, 832(1), p. 41. Institute of Physics Publishing IOP 10.3847/0004-637X/832/1/41

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The composition of a planet's atmosphere is determined by its formation, evolution, and present-day insolation. A planet's spectrum therefore may hold clues on its origins. We present a "chain" of models, linking the formation of a planet to its observable present-day spectrum. The chain links include (1) the planet's formation and migration, (2) its long-term thermodynamic evolution, (3) a variety of disk chemistry models, (4) a non-gray atmospheric model, and (5) a radiometric model to obtain simulated spectroscopic observations with James Webb Space Telescope and ARIEL. In our standard chemistry model the inner disk is depleted in refractory carbon as in the Solar System and in white dwarfs polluted by extrasolar planetesimals. Our main findings are: (1) envelope enrichment by planetesimal impacts during formation dominates the final planetary atmospheric composition of hot Jupiters. We investigate two, under this finding, prototypical formation pathways: a formation inside or outside the water iceline, called "dry" and "wet" planets, respectively. (2) Both the "dry" and "wet" planets are oxygen-rich (C/O < 1) due to the oxygen-rich nature of the solid building blocks. The "dry" planet's C/O ratio is <0.2 for standard carbon depletion, while the "wet" planet has typical C/O values between 0.1 and 0.5 depending mainly on the clathrate formation efficiency. Only non-standard disk chemistries without carbon depletion lead to carbon-rich C/O ratios >1 for the "dry" planet. (3) While we consistently find C/O ratios <1, they still vary significantly. To link a formation history to a specific C/O, a better understanding of the disk chemistry is thus needed.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Physics Institute > Space Research and Planetary Sciences
08 Faculty of Science > Physics Institute
08 Faculty of Science > Physics Institute > NCCR PlanetS

UniBE Contributor:

Mordasini, Christoph

Subjects:

500 Science > 520 Astronomy
600 Technology > 620 Engineering
500 Science > 530 Physics

ISSN:

0004-637X

Publisher:

Institute of Physics Publishing IOP

Language:

English

Submitter:

Janine Jungo

Date Deposited:

19 Jul 2017 08:24

Last Modified:

19 Jul 2017 08:24

Publisher DOI:

10.3847/0004-637X/832/1/41

BORIS DOI:

10.7892/boris.97238

URI:

https://boris.unibe.ch/id/eprint/97238

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