HD 35502: a hierarchical triple system with a magnetic B5IVpe primary

We present our analysis of HD 35502 based on high- and medium-resolution spectropolarimetric observations. Our results indicate that the magnetic B5IVsnp star is the primary component of a spectroscopic triple system and that it has an effective temperature of 18.4 +/- A 0.6 kK, a mass of 5.7 +/- A 0.6 M-aS (TM), and a polar radius of {+1.1}_{-0.5}{\rm R}. The two secondary components are found to be essentially identical A-type stars for which we derive effective temperatures (8.9 +/- A 0.3 kK), masses (2.1 +/- A 0.2 M-aS (TM)), and radii (2.1 +/- A 0.4 R-aS (TM)). We infer a hierarchical orbital configuration for the system in which the secondary components form a tight binary with an orbital period of 5.668 66(6) d that orbits the primary component with a period of over 40 yr. Least-Squares Deconvolution profiles reveal Zeeman signatures in Stokes indicative of a longitudinal magnetic field produced by the B star ranging from approximately -4 to 0 kG with a median uncertainty of 0.4 kG. These measurements, along with the line variability produced by strong emission in H alpha, are used to derive a rotational period of 0.853 807(3) d. We find that the measured i = 75 +/- A 5 km s(-1) of the B star then implies an inclination angle of the star's rotation axis to the line of sight of {+6}_{-10}{}. Assuming the Oblique Rotator Model, we derive the magnetic field strength of the B star's dipolar component and its obliquity. Furthermore, we demonstrate that the calculated Alfv,n radius and Kepler radius place HD 35502's central B star well within the regime of centrifugal magnetosphere-hosting stars.