A Nearly Polar Orbit for the Extrasolar Hot Jupiter WASP-79b

Abstract

We report the measurement of a spin-orbit misalignment for WASP-79b, a recently discovered, bloated hot Jupiter from the Wide Angle Search for Planets (WASP) survey. Data were obtained using the CYCLOPS2 optical-fiber bundle and its simultaneous calibration system feeding the UCLES spectrograph on the Anglo-Australian Telescope. We have used the Rossiter–McLaughlin effect to determine the sky-projected spin-orbit angle to be λ =− 106 +19 − 13 ◦ . This result indicates a significant misalignment between the spin axis of the host star and the orbital plane of the planet—the planet being in a nearly polar orbit. WASP-79 is consistent with other stars that have T eff > 6250 K and host hot Jupiters in spin-orbit misalignment.