Title: Characterization of the Wolf 1061 Planetary System Author: Stephen R. Kane, Kaspar von Braun, Gregory W. Henry, Miranda A. Waters, Tabetha S. Boyajian, Andrew W. Mann
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±0.0088~ solar radii, 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±1.8~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 ~0.15 as it exchanges angular momentum with the other planets in the system.
Title: Three planets orbiting Wolf 1061 Author: D.J. Wright, R.A. Wittenmyer, C.G. Tinney, J.S. Bentley, Jinglin Zhao
We use archival HARPS spectra to detect three planets orbiting the M3 dwarf Wolf1061 (GJ 628). We detect a 1.36 Mearth minimum-mass planet with an orbital period P = 4.888d (Wolf1061b), a 4.25 Mearth minimum-mass planet with orbital period P = 17.867d (Wolf1061c), and a likely 5.21 Mearth minimum-mass planet with orbital period P = 67.274d (Wolf1061d). All of the planets are of sufficiently low mass that they may be rocky in nature. The 17.867d planet falls within the habitable zone for Wolf 1061 and the 67.274d planet falls just outside the outer boundary of the habitable zone. There are no signs of activity observed in the bisector spans, cross-correlation full-width-half-maxima, Calcium H & K indices, NaD indices, or H-alpha indices near the planetary periods. We use custom methods to generate a cross-correlation template tailored to the star. The resulting velocities do not suffer the strong annual variation observed in the HARPS DRS velocities. This differential technique should deliver better exploitation of the archival HARPS data for the detection of planets at extremely low amplitudes.