Nissen (1976) classified HD 37776 as a helium-strong star.
Pedersen & Thomsen (1977) and Pedersen (1979)
discovered it was both a low amplitude spectrum and light variable with a
period of 
days. Walborn (1982) observed that its Si and
perhaps Mg lines also vary. Thompson & Landstreet (1985)
found an extraordinary double-wave magnetic curve with a period of 1.53869
days and argued that this star has a quadrupole-like field geometry.
Shore & Brown (1990) reported on its ultraviolet variability.
In years 5 and 6 of the FCAPT, I obtained 42 uvby observations of HD 37776.
Periodograms of this data agree with the above period. When I plotted them and
that of Pedersen & Thomsen with similar zero points, I found that a slight
adjustment was needed in the period. I adopted the zero phase of Thompson &
Landstreet
The error in the period is reduced by a factor of 10 compared to Thompson &
Landstreet.
Figure 1 (click here) shows the photometry with closed squares being the data of Pedersen & Thomsen and plus signs being FCAPT data. Both sets of data agree reasonably well. HD 37776 has a single maximum which occurs at approximately the same time in each color near phase 0.75. Better coverage of its peak is desirable. There is a minimum near phase 0.1. The photometric variation amplitudes are 0.03 mag in u, 0.04 mag in v, and 0.035 mag in b and y.