NGC 6611 601: a hot pre-main-sequence spectroscopic binary containing a centrifugal magnetosphere host star

W 601 (NGC 6611 601) is one of the handful known magnetic Herbig Ae/Be stars. We report analysis a large dataset high-resolution spectropolarimetry. The star previously unreported spectroscopic binary, consisting 2 B2 stars with mass ratio 1.8, masses 12 M$_\odot$ and 6.2 $M_\odot$, in an eccentric 110-day orbit. field belongs to secondary, B. H$\alpha$ emission consistent origin B's centrifugal magnetosphere; therefore not classical Be sense that its formed accretion disk. However, low value $\log{g} = 3.8$ determined via analysis, star's membership young NGC cluster, are most it being on pre-main sequence. rotational period inferred from variability line longitudinal $\langle B_z \rangle$ 1.13 d. Modelling Stokes $V$ indicates surface dipolar $B_{\rm d}$ between 6 $11$ kG. With strong emission, rapid rotation, field, B likely precursor H$\alpha$-bright B-type such as $\sigma$ Ori E. By contrast, primary apparently non-magnetic ($B_{\rm d} < 300$ G) sequence early star. In accordance expectations braking, more rapidly rotating than