A&A 454, 321-325 (2006)
Remarkable non-dipolar magnetic field of the Bp star HD 137509O. Kochukhov
Department of Astronomy and Space Physics, Uppsala University, 751 20, Uppsala, Sweden
(Received 30 January 2006 / Accepted 26 March 2006)
The southern magnetic Bp star HD 137509 exhibits complex rotational modulation of the longitudinal field and other magnetic observables. Interpretation of this magnetic variability in the framework of the low-order multipolar field models suggests a very strong quadrupolar component to dominate the surface field topology of HD 137509. I have examined the high-quality VLT/UVES spectra of HD 137509 and discovered resolved Zeeman split components in some of the spectral lines. The inferred mean surface field modulus, kG, agrees with the multipolar model predictions. This confirms the presence of an extremely strong non-dipolar magnetic field in HD 137509 and establishes this star as the object with the second-largest field among magnetic chemically peculiar stars.
Key words: line: profiles -- stars: magnetic fields -- stars: chemically peculiar -- stars: individual: HD 137509
© ESO 2006