Publications

Variable and Supersonic Winds in the Atmosphere of anUltrahot Giant Planet

Hot Jupiters receive intense irradiation from their stellar hosts. The resulting extreme environments in their atmospheres allow us to study the conditions that drive planetary atmospheric dynamics, e.g., global–scale winds. General circulation models predict day–to–nightside winds and equatorial jets with speeds of the order of a few km s–1. To test these models, we apply high–resolution transmission spectroscopy using the Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) spectrograph on the Large Binocular Telescope to study the atmosphere of KELT–9 b, an ultrahot Jupiter and currently the hottest known planet. We measure ~10 km s–1 day–to–nightside winds traced by Fe II features in the planet’s atmosphere. This is at odds with previous literature (including data taken with PEPSI), which report no significant day–to–nightside winds on KELT–9 b. We identify the cause of this discrepancy as due to an inaccurate ephemeris for KELT–9 b in previous literature.

2D maps of transmission spectra, focusing on the six Fe II absorption lines in the PEPSI 2018 data set chosen for fitting Kp and v_wind. The blue track is the planet’s atmospheric absorption while the red track is the Doppler shadow from the RME; both tracks only form during a transit. Top panel displays fully in-transit observations. Middle panel shows the best-fit model from MCMC sampling. The bottom panel presents the residuals (data-model).

Read more: Pai Asnodkar et al. 2022, AJ, 163, 155