Doppler tomography of the circumstellar disk of π Aquarii
Abstract
Aims: The work is aimed at studying the circumstellar disk of the bright classical binary Be star π Aqr.
Methods: We analysed variations of a double-peaked profile of the Hα 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.
Results: The dominant frequency in the power spectrum of the Hα V/R ratio is 0.011873 day-1, which corresponds to a period of 84.2(2) days and agrees with the earlier determined orbital period of the system, Porb = 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 Vin ≈ 450 km s-1 and Vout ≈ 200 km s-1, respectively, along with an extended stable region (spot) at Vx ≈ 225 km s-1 and Vy ≈ 100 km s-1. The disk radius of ≈65 R⊙ = 0.33 AU was estimated by assuming Keplerian motion of a particle on a circular orbit at the disk's outer edge.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- December 2013
- DOI:
- 10.1051/0004-6361/201322114
- arXiv:
- arXiv:1310.6499
- Bibcode:
- 2013A&A...560A..30Z
- Keywords:
-
- binaries: spectroscopic;
- circumstellar matter;
- stars: emission-line;
- Be;
- stars: individual: pi Aquarii;
- techniques: spectroscopic;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- 11 pages, 7 figures, 2 tables, published in A&