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

TL;DR

This paper reports the measurement of a nearly polar orbit for the hot Jupiter WASP-79b, revealing a significant spin-orbit misalignment using the Rossiter-McLaughlin effect, which contributes to understanding planetary migration.

Contribution

First measurement of a nearly polar orbit for WASP-79b, demonstrating a significant spin-orbit misalignment in a hot Jupiter system.

Findings

WASP-79b has a sky-projected spin-orbit angle of approximately -106 degrees.

The planet's orbit is nearly polar, indicating a significant misalignment.

WASP-79 is consistent with other hot stars hosting misaligned hot Jupiters.

Abstract

We report the measurement of a spin-orbit misalignment for WASP-79b, a recently discovered, bloated transiting hot Jupiter from the 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 lambda = -106+19-13 degrees. 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 Teff > 6250K and host hot Jupiters in spin-orbit misalignment.