  Recently, strong, globally-ordered magnetic fields have been detected in some
Herbig Ae and Be (HAeBe) stars, suggesting a possible evolutionary connection
to main sequence magnetic chemically peculiar Ap and Bp stars. We have
undertaken a detailed study of the binary system HD 72106, which contains a B9
magnetic primary and a HAeBe secondary, using the ESPaDOnS spectropolarimeter
mounted on the CFHT. A careful analysis of the very young primary reveals that
it has an approximately dipolar magnetic field geometry, strong chemical
peculiarities, and strong surface chemical abundance inhomogeneities. Thus the
primary is very similar to an Ap/Bp star despite having completed less then
1.5% of its main sequence life, and possibly still being on the pre-main
sequence. In contrast, a similar analysis of the secondary reveals solar
chemical abundances and no magnetic field.

Astrophysics