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Current models predict that binary interactions are a major ingredient in the formation of bipolar planetary nebulae (PNe) and pre-planetary nebulae (PPNe). Despite years of radial velocity (RV) monitoring, the paucity of known binaries amongst the latter systems means data are insufficient to examine this relationship in detail. In this work, we report on the discovery of a long-period (P  = 2654 ± 124 d) binary at the centre of the Galactic bipolar PPN IRAS 08005−2356 (V510 Pup), determined from long-term spectroscopic and near-infrared time-series data. The spectroscopic orbit is fitted with an eccentricity of 0.36 ± 0.05, which is similar to that of other long-period post-AGB binaries. Time-resolved H α profiles reveal high-velocity outflows (jets) with deprojected velocities up to 231 |$_{-27}^{+31}$| km s−1 seen at phases when the luminous primary is behind the jet. The outflow traced by H α is likely produced via accretion on to a main-sequence companion, for which we calculate a mass of 0.63 ± 0.13 M⊙. This discovery is one of the first cases of a confirmed binary PPN and demonstrates the importance of high-resolution spectroscopic monitoring surveys using large telescopes in revealing binarity among these systems. [ABSTRACT FROM AUTHOR]

The formation of Wolf-Rayet central stars of planetary nebulae ([WR] CSPNe) whose spec-troscopic 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 six [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 Porb = 4.04 ± 0.1 d. We measured a semi-amplitude of 62.3 ± 1.3 km s-1 that gives a companion mass of m2 > 0.5 M⊙ or m2 = 0.84 M⊙ (assuming i = 45°). The most plausible companion type is a massive white dwarf (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-ionization structures (e.g. as in NGC 6326) and collimated outflows (e.g. as in Fleming 1). The long 4.04 d orbital period is either anomalous (e.g. NGC 2346) or it may indicate that 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. [ABSTRACT FROM AUTHOR]