SIMBAD references

The frequency analysis of the photographic B light curve of the Mira star BS Lyr reveals besides the dominant period (P₁=304.7d) the unambiguous presence of a second one with P₂=272.3d. The analysis shows also the presence of the non-linear coupling terms between the two periodicities (1/P₁+1/P₂ and 1/P₂-1/P₁). The ratio between the two periods P₁/P₂=1.119±0.005 indicates that the two modes are the first (P₁) and the second (P₂) radial overtones. A third periodicity with P=179d could be also present, even if it is only marginally significant. It could correspond to the third overtone mode.