SIMBAD references

The work is aimed at studying the circumstellar disk of the bright classical binary Be star π Aqr. We analysed variations of a double-peaked profile of the H_α emission line in the spectrum of π Aqr that was observed in many phases during ∼40 orbital cycles in 2004-2013. We applied the discrete Fourier transform (DFT) method to search for periodicity in the peak intensity ratio (V/R). Doppler tomography was used to study the structure of the disk around the primary. The dominant frequency in the power spectrum of the H_α V/R ratio is 0.011873/day, which corresponds to a period of 84.2(2) days and agrees with the earlier determined orbital period of the system, P_orb=84.1 days. The V/R shows a sinusoidal variation that is phase-locked with the orbital period. Doppler maps of all our spectra show a non-uniform structure of the disk around the primary: a ring with the inner and outer radii at V_in≃450km/s and V_out ≃200km/s, respectively, along with an extended stable region (spot) at V_x ≃ 225km/s and V_y≃100km/s. The disk radius of ≃65R_☉=0.33AU was estimated by assuming Keplerian motion of a particle on a circular orbit at the disk's outer edge.