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 observed fluctuations in the intensities of the star's neutral helium lines on plates from 1908 to 1911. These findings were corroborated by A. D. Thackeray in 1966.