| magnetic star |
|
A star with an exceptionally strong magnetic field. Magnetic fields more than a thousand times stronger than the Sun's general field have been measured for a group of A stars, which also have peculiar spectra and so are classified as Ap stars. In the presence of a magnetic field, the lines produced in the stellar spectrum are split into polarized components (the Zeeman effect). Although the lines are usually too broad for the split components to be resolved, the change in polarization across the broadened spectral lines can be measured and interpreted in terms of a magnetic field strength. In almost all cases, the fields and spectral line strengths vary regularly. This observation can be accounted for if the rotation and magnetic axes of the stars do not coincide. See also: peculiar star. |