XO-5b: A Transiting Jupiter-sized Planet With A Four Day Period

TL;DR

This paper reports the discovery and characterization of XO-5b, a Jupiter-sized exoplanet with a four-day orbit, which exhibits a larger mass and gravity than typical for its period, challenging existing empirical relationships.

Contribution

It provides detailed measurements of XO-5b's physical properties and highlights deviations from established planetary mass-period relations, offering insights into planetary formation.

Findings

XO-5b has a mass of 1.15 Mjup and a radius of 1.15 Rjup.

The planet's surface gravity is significantly higher than expected.

XO-5b's properties challenge existing empirical planetary relationships.

Abstract

The star XO-5 (GSC 02959-00729, V=12.1, G8V) hosts a Jupiter-sized, Rp=1.15+/-0.12 Rjup, transiting extrasolar planet, XO-5b, with an orbital period of P=4.187732+/-0.00002 days. The planet mass (Mp=1.15+/-0.08 Mjup) and surface gravity (gp=22+/-5 m/s^2) are significantly larger than expected by empirical Mp-P and Mp-P-[Fe/H] relationships. However, the deviation from the Mp-P relationship for XO-5b is not large enough to suggest a distinct type of planet as is suggested for GJ 436b, HAT-P-2b, and XO-3b. By coincidence XO-5 overlies the extreme H I plume that emanates from the interacting galaxy pair NGC 2444/NGC 2445 (Arp 143).