The kinematics of the quadrupolar nebula M 1–75 and the identification of its central star

Abstract

Context. The link between the shaping of bipolar planetary nebulae and their central stars is still poorly understood. Aims. The kinematics and shaping of the multipolar nebula M 1-75 are hereby investigated, and the location and nature of its central star are briefly discussed. Methods. Fabry-Perot data from GHFAS on the WHT sampling the Doppler shift of the (Nii) 658.3 nm line are used to study the dynamics of the nebula, by means of a detailed 3-D spatio-kinematical model. Multi-wavelength images and spectra from the WFC and IDS on the INT, and from ACAM on the WHT, allowed us to constrain the parameters of the central star. Results. The two pairs of lobes, angularly separated by� 22 � , were ejected simultaneously approx.� 3500-5000 years ago, at the adopted distance range from 3.5 to 5.0 kpc. The larger lobes show evidence of a slight degree of point symmetry. The shaping of the nebula could be explained by wind interaction in a system consisting of a post-AGB star surrounded by a disc warped by radiative instabilities. This requires the system to be a close binary or a single star which engulfed a planet as it died. On the other hand, we present broad- and narrow-band images and a low S/N optical spectrum of the highly-reddened, previously unnoticed star which is likely the nebular progenitor. Its estimated V− I colour allows us to derive a rough estimate of the parameters and nature of the central star.