The signature of wind patterns caused by the interplay of rotation and energy redistribution in hot Jupiters is detectable at high spectral resolution , yet no direct comparison has been attempted between predictions from general circulation models ( GCMs ) and observed high-resolution spectra .
We present the first of such comparisons on near-infrared transmission spectra of the hot Jupiter HD 189733b .
Exploring twelve rotation rates and two chemical regimes , we have created model spectra from 3-D GCMs and cross-correlated them with the observed spectra .
Comparing our models against those of HD 189733b , we obtain three key results : ( 1 ) we confirm CO and H _ { 2 } O in the planet ’ s atmosphere at a detection significance of 8.2 \sigma ; ( 2 ) we recover the signature of \sim km/s day-to-night winds at \sim mbar pressures ; and ( 3 ) we constrain the rotation period of the planet to between 1.2 and 4.69 days ( synchronous rotation ( 2.2 days ) remains consistent with existing observations ) .
Our results do not suffer from the shortcomings of 1-D models as cross correlation templates – mainly that these models tend to over-constrain the slower rotation rates and show evidence for anomalous blue shifts .
Our 3-D models instead match the observed line-of-sight velocity of this planet by self-consistently including the effects of high-altitude day-to-night winds .
Overall , we find a high degree of consistency between HD 189733b observations and our GCM-based spectra , implying that the physics and chemistry are adequately described in current 3-D forward models for the purpose of interpreting observations at high spectral resolution .