The Jupiter Twin HD 154345b

TL;DR

This paper reports the discovery of a Jupiter-like exoplanet orbiting the nearby G8 dwarf HD 154345, with detailed analysis ruling out stellar activity as the cause of observed radial velocity signals.

Contribution

First detection of a Jupiter twin around HD 154345, including characterization of its orbit and ruling out stellar activity as the source of signals.

Findings

Exoplanet has a minimum mass of 0.95 Jupiter masses.

Orbital period of 9.2 years at 4.2 AU.

Star exhibits a 9-year activity cycle not responsible for radial velocity variations.

Abstract

We announce the discovery of a twin of Jupiter orbiting the slightly metal-poor ([Fe/H] = -0.1) nearby (d = 18 pc) G8 dwarf HD 154345. This planet has a minimum mass of 0.95 Jupiter masses and a 9.2 year, circular orbit with radius 4.2 AU. There is currently little or no evidence for other planets in the system, but smaller or exterior planets cannot yet be ruled out. We also detect a ~ 9-year activity cycle in this star photometrically and in chromospheric emission. We rule out activity cycles as the source of the radial velocity variations by comparison with other cycling late-G dwarfs.