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

8 páginas, 5 figuras, 3 tablas.-- El Pdf del artículo es la versión pre-print: arXiv:1006.2398v1.-- et al.
[Context]: The link between how bipolar planetary nebulae are shaped and their central stars is still poorly understood. [Aims]: This paper investigates the kinematics and shaping of the multipolar nebula M 1–75, and briefly discusses the location and nature of its central star. [Methods]: Fabry-Perot data from GHαFAS on the WHT that samples the Doppler shift of the [Nii] 658.3 nm line are used to study the dynamics of the nebula by means of a detailed 3D spatio-kinematical model. Multi-wavelength images and spectra from the WFC and IDS on the INT, as well as 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 a slight degree of point symmetry. The formation 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 that 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 that 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.