EPIC211089792 b: an aligned and inflated hot jupiter in a young visual binary

TL;DR

This paper reports the discovery and characterization of EPIC211089792 b, a young, aligned hot Jupiter in a binary system, with detailed measurements of its properties and potential for atmospheric studies.

Contribution

It presents the discovery, orbital and physical characterization, and the alignment measurement of a new hot Jupiter in a young binary system, highlighting its suitability for atmospheric observations.

Findings

Planet has a 3.25-day orbit with 0.73 Mjup mass and 1.19 Rjup radius.

System is likely about 450 million years old.

Planet's orbit is aligned with the stellar spin.

Abstract

In the present paper we report the discovery of a new hot Jupiter, EPIC211089792 b, first detected by the Super-WASP observatory and then by the K2 space mission during its campaign 4. The planet has a period of 3.25d, a mass of 0.73 +/- 0.04 Mjup, and a radius of 1.19 +/- 0.02 Rjup. The host star is a relatively bright (V=12.5) G7 dwarf with a nearby K5V companion. Based on stellar rotation and the abundance of Lithium, we find that the system might be as young as about 450 Myr. The observation of the Rossiter-McLaughlin effect shows the planet is aligned with respect to the stellar spin. Given the deep transit (20mmag), the magnitude of the star and the presence of a nearby stellar companion, the planet is a good target for both space- and ground-based transmission spectroscopy, in particular in the near-infrared where the both stars are relatively bright.