Abstract The carbon-rich star V Hydrae is known to be in its transition from the asymptotic giant branch phase to a bipolar planetary nebula. However, the origin of its bipolar shape, as well as its long-term periodic obscuration, are not well understood. Using high-resolution spectra from the HERMES/Mercator spectrograph spanning over 10-yr monitoring, we disentangled the orbital signal from the intrinsic Mira-like variations of V Hya. The orbital solution obtained is compatible with the light-curve modulation, which we interpret as an obscuration caused by an extended dusty environment surrounding the unseen companion. Additionally, we report high-velocity phase-dependent absorption features in the sodium doublet and explain them by the presence of a conical jet ejected from the (accretion disc of the) companion. We confront our binary scenario with previous radio observations and discuss how this jet could shape the large-scale bipolar outflow of the system.
Planquart et al. (Fri,) studied this question.
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