Characterization of the Wolf 1061 Planetary System

TL;DR

This study provides detailed stellar and planetary characterization of Wolf 1061, including a direct measurement of stellar radius, rotation period, and habitable zone boundaries, confirming the planetary signals are not stellar in origin.

Contribution

The paper offers the first direct stellar radius measurement for Wolf 1061 and refines the habitable zone boundaries using new observational data and orbital dynamics simulations.

Findings

Stellar radius measured as 0.3207 R_sun

Stellar rotation period determined as 89.3 days

Habitable zone extends from 0.09 to 0.23 AU

Abstract

A critical component of exoplanetary studies is an exhaustive characterization of the host star, from which the planetary properties are frequently derived. Of particular value are the radius, temperature, and luminosity, which are key stellar parameters for studies of transit and habitability science. Here we present the results of new observations of Wolf~1061, known to host three super-Earths. Our observations from the Center for High Angular Resolution Astronomy (CHARA) interferometric array provide a direct stellar radius measurement of $0.3207 \pm 0.0088$~$R_{\odot}$, from which we calculate the effective temperature and luminosity using spectral energy distribution models. We obtained seven years of precise, automated photometry that reveals the correct stellar rotation period of $89.3\pm1.8$~days, finds no evidence of photometric transits, and confirms the radial velocity signals are not due to stellar activity. Finally, our stellar properties are used to calculate the extent of the Habitable Zone for the Wolf~1061 system, for which the optimistic boundaries are 0.09--0.23~AU. Our simulations of the planetary orbital dynamics shows that the eccentricity of the Habitable Zone planet oscillates to values as high as $\sim$0.15 as it exchanges angular momentum with the other planets in the system.