In 1965, W. P. Bidelman discovered that the intensities of the star's neutral helium lines had varied on photographic plates taken over the period 1908 to 1911. This variation was confirmed by A. D. Thackeray in 1966.
In 1965, W. P. Bidelman detected changes in the star's neutral helium line intensities recorded from 1908 to 1911. These results were independently verified by A. D. Thackeray in 1966.