# WASP-180Ab: Doppler tomography of an hot Jupiter orbiting the primary star in a visual binary

## TL;DR

This paper reports the discovery and characterization of WASP-180Ab, a hot Jupiter in a binary system, using Doppler tomography and radial velocities, revealing its misaligned, retrograde orbit around an F7 star.

## Contribution

It presents the first Doppler tomography detection of a hot Jupiter in a binary system, demonstrating the planet's misaligned orbit and its host star's properties.

## Key findings

- WASP-180Ab is a 0.9 M_Jup hot Jupiter in a misaligned, retrograde orbit.
- The host star is part of a binary system with a secondary star contributing 30% of the light.
- The planet's orbit is confirmed through Doppler shadow detection and radial velocity measurements.

## Abstract

We report the discovery and characterisation of WASP-180Ab, a hot Jupiter confirmed by the detection of its Doppler shadow and by measuring its mass using radial velocities. We find the 0.9 $\pm$ 0.1 $M_{\rm Jup}$, 1.24 $\pm$ 0.04 $R_{\rm Jup}$ planet to be in a misaligned, retrograde orbit around an F7 star with $T_{\rm eff}$ = 6500K and a moderate rotation speed of vsini = 19.9 km s$^{-1}$. The host star is the primary of a $V$ = 10.7 binary, where a secondary separated by 5$''$ ($\sim$1200 AU) contributes $\sim$30% of the light. WASP-180Ab therefore adds to a small sample of transiting hot Jupiters known in binary systems. A 4.6-day modulation seen in the WASP data is likely to be the rotational modulation of the companion star, WASP-180B.