Examination of the Interstellar Spectrum of AE Aur for Long‐Term Changes

The runaway O9.5 V star AE Aur is moving across the line of sight behind the curtain provided by the emission/reflection nebula IC 405. The interstellar line spectrum of AE Aur was examined on a HIRES spectrogram obtained in 1998 to determine if there had been any change since the original high‐resolution observations by Adams in the 1940s. No equivalent widths were published by Adams, so only a comparison of radial velocities was possible. No significant changes over the intervening half‐century were detected; during that time the cross motion of AE Aur in the plane of the sky amounted to about 1450 AU. Similarly, no convincing changes were found in the interstellar Ca ii lines of the runaway O star μ Col.