Magnetic fields on O-Class stars

The primary method by which astronomers can measure magnetic field strength on stars is the Zeeman effect. This effect is the splitting of spectral lines into two due to the magnetic field's effect on the quantum structure of the orbitals. For massive O-class stars, their spectra are largely featureless in the visual portion of the spectra due to an insufficient number of atoms with electrons in the necessary orbitals to undergo transitions which can produce visual spectral lines. Thus, determining whether or not these stars have magnetic fields has been a unique challenge.

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