Vol. 560
In section 7. Stellar structure and evolution

Doppler tomography of the circumstellar disk of pi Aquarii

This study reports the presence of a coherent emission structure in the extended disk of the classical Be star pi Aqr, a known binary system with an orbital period of 84 days and a range of emission line activity states. Perhaps the most notable, and promising, feature of this study is the collaboration of professional and amateur astronomers in a spectroscopic study of a particularly interesting physical process in Be stars. The resulting sample, 286 high-resolution (10000-22000) spectra, of which more than 80% are from amateurs in 6 countries using small (200 to 400 cm) telescopes, is a rich archive covering about a decade with very high cadence. The period found for the V/R variations is the same as the orbital period, permitting a very detailed Doppler tomographic construction that shows an H alpha concentration toward the secondary that remains coherent over 40 orbital cycles, and indications of more extended structures within the disk around the primary (more massive) star. The primary's radius appears to be significantly larger than its expected ZAMS value.