The paper is titled «Demonstration of a near - IR line - referenced electro - optical laser frequency comb for precision radial velocity measurements in astronomy.» (keckobservatory.org)
The research team took a series of radial velocity measurements of Kapteyn's Star's light between May and December 2013 using the High Accuracy Radial Velocity Planet Searcher, or HARPS, a high - resolution spectrograph mounted on ESO's 3.6 - meter telescope at the La Silla Observatory in Chile, which clearly revealed the presence of two distinct signals, indicating the presence of two high - mass planets. (americaspace.com)
The host star is bright (V = 11.2, J = 9.1) and so may be a good target for precise radial velocity measurements. (arxiv.org)