Three planets orbiting Wolf 1061

TL;DR

This paper reports the discovery of three low-mass planets orbiting Wolf 1061 using archival HARPS data, including one within the habitable zone, with improved velocity analysis techniques enhancing detection sensitivity.

Contribution

The study introduces a custom cross-correlation method that reduces annual variations in velocity data, enabling more precise detection of low-amplitude planetary signals.

Findings

Detected three low-mass planets around Wolf 1061.

One planet resides within the habitable zone.

New velocity analysis technique improves detection sensitivity.

Abstract

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.