Three WASP-South transiting exoplanets: WASP-74b, WASP-83b & WASP-89b

TL;DR

This paper reports the discovery of three new transiting hot Jupiters by WASP-South, detailing their properties, host stars, and potential for further study, especially focusing on WASP-89b's magnetic activity and star spots.

Contribution

First discovery of three transiting hot Jupiters with detailed characterization of their orbits, masses, radii, and host star properties, including magnetic activity and star spot interactions.

Findings

WASP-74b is a bloated hot Jupiter orbiting a bright star.

WASP-83b is a Saturn-mass planet with a 5-day orbit.

WASP-89b is a massive, eccentric planet around an active K star.

Abstract

We report the discovery of three new transiting hot Jupiters by WASP-South together with the TRAPPIST photometer and the Euler/CORALIE spectrograph. WASP-74b orbits a star of V = 9.7, making it one of the brighter systems accessible to Southern telescopes. It is a 0.95 M_Jup planet with a moderately bloated radius of 1.5 R_Jup in a 2-d orbit around a slightly evolved F9 star. WASP-83b is a Saturn-mass planet at 0.3 M_Jup with a radius of 1.0 R_Jup. It is in a 5-d orbit around a fainter (V = 12.9) G8 star. WASP-89b is a 6 M_Jup planet in a 3-d orbit with an eccentricity of e = 0.2. It is thus similar to massive, eccentric planets such as XO-3b and HAT-P-2b, except that those planets orbit F stars whereas WASP-89 is a K star. The V = 13.1 host star is magnetically active, showing a rotation period of 20.2 d, while star spots are visible in the transits. There are indications that the planet's orbit is aligned with the stellar spin. WASP-89 is a good target for an extensive study of transits of star spots.