An astrometric planetary companion candidate to the M9 Dwarf TVLM 513-46546

TL;DR

This paper reports the first radio astrometric detection of a Saturn-like planet orbiting an ultra-cool dwarf star, challenging existing planet formation theories with its unique characteristics.

Contribution

It presents the discovery of a giant-mass planet around an M9 dwarf via radio astrometry, a novel detection method for such systems.

Findings

Detected a planet with 0.35-0.42 M_J at 0.3 AU from TVLM 513-46546.

First astrometric planet detection at radio wavelengths.

Planet challenges current planet formation models.

Abstract

Astrometric observations of the M9 dwarf TVLM 513$-$46546 taken with the VLBA reveal an astrometric signature consistent with a period of 221 $\pm$ 5 days. The orbital fit implies that the companion has a mass m$_{p}$ = 0.35$-$0.42 $M_{J}$, a circular orbit ($e \simeq 0$), a semi-major axis a = 0.28$-$0.31 AU and an inclination angle i = 71$-$88$^\circ$. The detected companion, TVLM~513$b$, is one of the few giant-mass planets found associated to UCDs. The presence of a Saturn-like planet on a circular orbit, 0.3 AU from a 0.06$-$0.08 $M_\odot$ star, represents a challenge to planet formation theory. This is the first astrometric detection of a planet at radio wavelengths.