High Resolution Transmission Spectroscopy as a Diagnostic for Jovian Exoplanet Atmospheres: Constraints from Theoretical Models

Kempton, Eliza; Perna, Rosalba; Heng, Kevin (2014). High Resolution Transmission Spectroscopy as a Diagnostic for Jovian Exoplanet Atmospheres: Constraints from Theoretical Models. Astrophysical journal, 795(1), p. 24. Institute of Physics Publishing IOP 10.1088/0004-637X/795/1/24

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We present high resolution transmission spectra of giant planet atmospheres from a coupled 3-D atmospheric dynamics and transmission spectrum model that includes Doppler shifts which arise from winds and planetary motion. We model jovian planets covering more than two orders of magnitude in incident flux, corresponding to planets with 0.9 to 55 day orbital periods around solar-type stars. The results of our 3-D dynamical models reveal certain aspects of high resolution transmission spectra that are not present in simple 1-D models. We find that the hottest planets experience strong substellar to anti-stellar (SSAS) winds, resulting in transmission spectra with net blue shifts of up to 3 km s−1, whereas less irradiated planets show almost no net Doppler shifts. Compared to 1-D models, peak line strengths are significantly reduced for the hottest atmospheres owing to Doppler broadening from a combination of rotation (which is faster for close-in planets under the assumption of tidal locking) and atmospheric winds. Finally, high resolution transmission spectra may be useful in studying the atmospheres of exoplanets with optically thick clouds since line cores for very strong transitions should remain optically thick to very high altitude. High resolution transmission spectra are an excellent observational test for the validity of 3-D atmospheric dynamics models, because they provide a direct probe of wind structures and heat circulation. Ground-based exoplanet spectroscopy is currently on the verge of being able to verify some of our modeling predictions, most notably the dependence of SSAS winds on insolation. We caution that interpretation of high resolution transmission spectra based on 1-D atmospheric models may be inadequate, as 3-D atmospheric motions can produce a noticeable effect on the absorption signatures.

Item Type:

Journal Article (Original Article)

Division/Institute:

10 Strategic Research Centers > Center for Space and Habitability (CSH)

UniBE Contributor:

Heng, Kevin

Subjects:

500 Science > 520 Astronomy

ISSN:

0004-637X

Publisher:

Institute of Physics Publishing IOP

Language:

English

Submitter:

Danielle Zemp

Date Deposited:

13 Oct 2014 13:42

Last Modified:

28 Jun 2016 17:13

Publisher DOI:

10.1088/0004-637X/795/1/24

ArXiv ID:

1409.1250

BORIS DOI:

10.7892/boris.59270

URI:

https://boris.unibe.ch/id/eprint/59270

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