The High-resolution Transmission Spectrum of HD 189733b Interpreted with Atmospheric Doppler Shifts from Three-dimensional General Circulation Models

The interplay of rotation and energy redistribution in the atmospheres of hot Jupiters produces complex wind patterns affecting the shape and shift of spectral lines. This signature is detectable at high spectral resolution, however no direct comparison has been attempted so far between predictions from general circulation models (GCMs) and data. Here we present the first of such comparisons of near-infrared transmission spectra of the hot Jupiter HD 189773b (HD189). Exploring different rotation rates, we have created model transmission spectra from 3D GCMs and cross-correlated (CC) these models with observed spectra of HD189. Comparing our models against data, we obtain three key results: atmospheric CO and H2O are detected at 8.2 sigma; strong day-to-night winds are recovered at ~mbar pressures; and from a combination of phase curve inspection and CC analysis, we constrain the rotation period of the planet to between 1.2 and 4.69 days, leaving synchronous rotation consistent with existing observations. The CC results using our 3D models differ from previous studies using 1D spectral models in two key ways: (1) 1D models over-constrain the slower rotation rates because they do not account for atmospheric dynamics, which dominate the atmospheric velocity dispersion in cases in which the planet is slowly rotating, and (2) using the GCM-based spectra as CC templates, we remove spurious blue-shifts in the transmission spectrum of HD189. We instead reproduce the observed line-of-sight velocity of this planet by self-consistently including the effects of high-altitude day-to-night winds in our models. Overall, we find a high degree of consistency between the observed spectrum of HD189 and the ones produced from our 3D models, implying that the physics and chemistry are adequately described in 3D models for the purpose of interpreting observations at high spectral resolution. [abridged]