New Insights Into the Dynamics and Expansion Parallax of Nebulae around Symbiotic Stars

Abstract

Currently, there are a dozen known spatially resolved nebulae around symbiotic stars. We summarize their properties, focusing on their dynamical ones. Then, new results about the determination of the expansion in the plane of the sky of the nebulae around Hen 2-104 and Hen 2-147, which allows us to gain important information about their dynamics and to discuss their distance via the expansion parallax method, will be described. Finally, the discussion will be extended to bipolar nebulae presently classified as planetary nebulae, but which might instead host a symbiotic star, and in particular to the remarkable cases of Mz 3 and M 2-9.