A Substellar Companion in a 1.3 yr Nearly-circular Orbit of HD 16760

TL;DR

This paper reports the discovery of a nearly circular orbiting substellar companion around HD 16760, with a mass near the planet/brown dwarf boundary, detected through precise Doppler measurements.

Contribution

It presents the detection and characterization of a unique substellar companion with a nearly circular orbit and a mass close to the planet/brown dwarf transition.

Findings

Companion mass of approximately 13.1 Jupiter masses.

Orbital period of about 466 days.

Orbit eccentricity of 0.084, nearly circular.

Abstract

We report the detection of a substellar companion orbiting the G5 dwarf HD 16760 from the N2K sample. Precise Doppler measurements of the star from Subaru and Keck revealed a Keplerian velocity variation with a period of 466.47+-0.35 d, a semiamplitude of 407.71+-0.84 m/s, and an eccentricity of 0.084+-0.003. Adopting a stellar mass of 0.78+-0.05 M_Sun, we obtain a minimum mass for the companion of 13.13+-0.56 M_JUP, which is close to the planet/brown-dwarf transition, and the semimajor axis of 1.084+-0.023 AU. The nearly circular orbit despite the large mass and intermediate orbital period makes this companion unique among known substellar companions.