Abell 41: nebular shaping by a binary central star?

We present the first detailed spatio-kinematical analysis and modelling of the planetary nebula Abell~41, which is known to contain the well-studied close-binary system MT Ser. This object represents an important test case in the study of the evolution of planetary nebulae with binary central stars as current evolutionary theories predict that the binary plane should be aligned perpendicular to the symmetry axis of the nebula. Longslit observations of the \NII\ emission from Abell~41 were obtained using the Manchester Echelle Spectrometer on the 2.1-m San Pedro Mártir Telescope. These spectra, combined with deep, narrowband imagery acquired using ACAM on the William Herschel Telescope, were used to develop a spatio-kinematical model of \NII\ emission from Abell~41. The best fitting model reveals Abell~41 to have a waisted, bipolar structure with an expansion velocity of $\sim$40\kms{} at the waist. The symmetry axis of the model nebula is within 5$^\circ$ of perpendicular to the orbital plane of the central binary system. This provides strong evidence that the close-binary system, MT Ser, has directly affected the shaping of its host nebula, Abell~41.