New distance measurements to the Pleiades and Formula Persei clusters

We apply the new distance measuring technique of Hendry, O'Dell & Collier Cameron to the Pleiades and |α| Persei clusters. The method relies on knowledge of the periods, rotational velocities and angular diameters of a small sample of the late-type stars within each cluster. The angular diameters of these stars were found by recalibrating the Barnes–Evans surface brightness relation for an improved calibration sample in the spectral range |-0.15 ≤ (B-V)₀≤ 1.35|⁠. Applying our new distance method, we derive a true distance modulus |(m-M)₀=5.60| mag for the Pleiades, and |(m-M)₀=6.35| mag for |α| Persei. Our determination of the Pleiades distance is in good agreement with previous zero-age main-sequence fitting techniques, whereas our distance for |α| Persei appears substantially greater. In response to the greater distance for |α| Persei, we apply the relatively recent semi-empirical main-sequence fitting method of Vandenberg & Poll, which yields a true distance modulus of |(m-M)₀=6.25| mag, thereby providing substantial support for our findings.