| Résumé | 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 ± 0.6 kK, a mass of 5.7 ± 0.6 M⊙, and a polar radius of
3.0 +1.1 −0.5 R ⊙
3.0−0.5+1.1R⊙
. The two secondary components are found to be essentially identical A-type stars for which we derive effective temperatures (8.9 ± 0.3 kK), masses (2.1 ± 0.2 M⊙), and radii (2.1 ± 0.4 R⊙). 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 V 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 Hα, are used to derive a rotational period of 0.853 807(3) d. We find that the measured v sin i = 75 ± 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
24 +6 −10 ∘
24−10+6∘
. Assuming the Oblique Rotator Model, we derive the magnetic field strength of the B star's dipolar component (
14 +9 −3 kG
14−3+9kG
) and its obliquity (
63±13deg
63±13deg
). Furthermore, we demonstrate that the calculated Alfvén radius (
41 +17 −6 R ∗
41−6+17R∗
) and Kepler radius (
2.1 +0.4 −0.7 R ∗
2.1−0.7+0.4R∗
) place HD 35502's central B star well within the regime of centrifugal magnetosphere-hosting stars. |
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