A hot Jupiter orbiting the 1.7 Msun Subgiant HD102956

TL;DR

This paper reports the discovery of a hot Jupiter orbiting a 1.7 solar mass subgiant star, highlighting the occurrence and distribution of close-in giant planets around intermediate-mass stars.

Contribution

It presents the detection of the most massive star known to host a hot Jupiter and analyzes the occurrence rate of such planets around similar stars.

Findings

A hot Jupiter was found orbiting HD102956 at 0.081 AU.

Approximately 0.5-2.3% of similar stars host close-in giant planets.

The distribution of planets suggests an exaggerated period valley around intermediate-mass stars.

Abstract

We report the detection of a giant planet in a 6.4950 day orbit around the 1.7 Msun subgiant HD102956. The planet has a semimajor axis a = 0.081 AU and minimum mass Msini = 0.96 Mjup. HD102956 is the most massive star known to harbor a hot Jupiter, and its planet is only the third known to orbit within 0.6 AU of a star more massive than 1.5 Msun. Based on our sample of 137 subgiants with M* > 1.45 Msun we find that 0.5-2.3% of A-type stars harbor a close-in planet (a < 0.1 AU) with Msini > 1 Mjup, consistent with hot-Jupiter occurrence for Sun-like stars. Thus, the paucity of planets with 0.1 < a/AU < 1.0 around intermediate-mass stars may be an exaggerated version of the "period valley" that is characteristic of planets around Sun-like stars.