The 34-KILOGAUSS Magnetic Field of HD 215441.

The AOp star HD 215441 has a magnetic field sufficiently strong and uniform to show distinct resolution of many spectrum lines into the ir and components of their Zeeman patterns. The mean field intensity derived from four plates is +34400+ 266 gauss. The field fluctuates irregularly, but 20 plates all show the same polarity. Random variations in radial velocity in the range +3.0 to -8.9 km/sec have been observed. The degree of spectral peculiarity is not extreme, although lines of Si ii, Ti ii, and Cr ii are strong, and the anomalous presence of lines of Fe iii has been noted. Sharp lines of Ca ii, showing a relatively weak Zeeman effect, are judged to arise in a circumstellar cloud having an effective height of 1.2 stellar radii above the surface and showing a mean outward velocity of S km/sec. The magneticenergy density at the surface is 4.6 X 10 ergs/cm3, and the magnetic pressure is sufficient to dominate over the gas pressure in the outer layers of the star. If a 34-kilogauss field prevails throughout the interior, the total internal magnetic energy is about 1041 ergs.