Title: A radial velocity survey for post-common-envelope Wolf-Rayet central stars of planetary nebulae: First results and discovery of the close binary nucleus of NGC 5189 Authors: Manick, Rajeev ×Miszalski, BrentMcBride, Vanessa # Issue Date: 15-Jan-2015 Publisher: Priestley and Weale Series Title: Monthly Notices of the Royal Astronomical Society vol:2 issue:448 pages:1789-1806 Article number: 448 Abstract: The formation of Wolf-Rayet central stars of planetary nebulae ([WR] CSPNe) whose spectroscopic appearance mimics massive WR stars remains poorly understood. Least understood is the nature and frequency of binary companions to [WR] CSPNe that may explain their H-deficiency. We have conducted a systematic radial velocity (RV) study of 6 [WR] CSPNe to search for post-common-envelope (post-CE) [WR] binaries. We used a cross-correlation method to construct the RV time-series as successfully done for massive close binary WR stars. No significant RV variability was detected for the late-[WC] type nuclei of Hen~2-113, Hen~3-1333, PMR~2 and Hen~2-99. Significant, large-amplitude variability was found in the [WC4] nucleus of NGC~5315. In the [WO1] nucleus of NGC~5189 we discovered significant periodic variability that reveals a close binary with $P_\mathrm{orb}=4.04\pm0.1$ d. We measured a semi-amplitude of $62.3\pm1.3$ km s$^{-1}$ that gives a companion mass of $m_2\ge0.5$ $M_\odot$ or $m_2=0.84$ $M_\odot$ (assuming $i=45^\circ$). The most plausible companion type is a massive WD as found in Fleming~1. The spectacular nebular morphology of NGC~5189 fits the pattern of recently discovered post-CE PNe extremely well with its dominant low-ionisation structures (e.g. as in NGC~6326) and collimated outflows (e.g. as in Fleming~1). The anomalously long 4.04 d orbital period is either a once-off (e.g. NGC~2346) or it may indicate there is a sizeable population of [WR] binaries with massive WD companions in relatively wide orbits, perhaps influenced by interactions with the strong [WR] wind. URI: http://mnras.oxfordjournals.org/content/448/2/1789.full.pdf+html ISSN: 0035-8711 Publication status: published KU Leuven publication type: IT Appears in Collections: Institute of Astronomy