BEBOP III. Observations and an independent mass measurement of Kepler-16 (AB) b – the first circumbinary planet detected with radial velocities

The radial velocity method is amongst the most robust and established means of detecting exoplanets. Yet, it has so far failed to detect circumbinary planets despite their relatively high occurrence rates. Here, we report velocimetric measurements Kepler-16A, obtained with SOPHIE spectrograph, at Observatoire de Haute-Provence's 193cm telescope, collected during BEBOP survey for planets. Our mark first detection a planet, independently determining mass Kepler-16~(AB)~b be $0.313 \pm 0.039\,{\rm M}_{\rm Jup}$, value in agreement eclipse timing variations. observations demonstrate capability achieve photon-noise precision accuracy on single-lined binaries, our final reaching $\rm 1.5~m\,s^{-1}$ binary planetary signals. analysis paves way more planet detections using velocities which will increase small sample currently known systems statistically relevant numbers, that also provides weaker biases. data contain long-term signal, associate magnetic cycle primary star.