MASCARA-1 b: A hot Jupiter transiting a bright $m_V=8.3$ A-star in a misaligned orbit

TL;DR

MASCARA-1 b is a hot Jupiter orbiting a bright, rapidly rotating A-star with a misaligned orbit, high temperature, and potential for atmospheric studies, marking the first discovery by the MASCARA survey.

Contribution

First exoplanet discovery using MASCARA, demonstrating its capability to find hot Jupiters around bright early-type stars.

Findings

Orbit misalignment suggests complex formation history.

High equilibrium temperature makes it ideal for atmospheric studies.

Bright host star facilitates detailed follow-up observations.

Abstract

We report the discovery of MASCARA-1 b, the first exoplanet discovered with the Multi-site All-Sky CAmeRA (MASCARA). It is a hot Jupiter orbiting a bright $m_V=8.3$, rapidly rotating ($v\sin i_\star > 100~\rm{km~s}^{-1}$) A8 star with a period of $2.148780\pm8\times10^{-6} ~\rm{days}$. The planet has a mass and radius of $3.7\pm0.9~\rm{M}_{\rm{Jup}}$ and $1.5\pm0.3~\rm{R}_{\rm{Jup}}$, respectively. As with most hot Jupiters transiting early-type stars we find a misalignment between the planet orbital axis and the stellar spin axis, which may be signature of the formation and migration histories of this family of planets. MASCARA-1 b has a mean density of $1.5\pm0.9~\rm{g~cm^{-3}}$ and an equilibrium temperature of $2570^{+50}_{-30}~\rm{K}$, one of the highest temperatures known for a hot Jupiter to date. The system is reminiscent of WASP-33, but the host star lacks apparent delta-scuti variations, making the planet an ideal target for atmospheric characterization. We expect this to be the first of a series of hot Jupiters transiting bright early-type stars that will be discovered by MASCARA.