The onset of jets in classical novae

We present two further classical novae, V906 Car and V5668 Sgr, which show jets and accretion disc spectral signatures in their H α complexes throughout the first 1000 d following their eruptions. From extensive densely time-sampled spectroscopy, we measure the appearance of the first high-velocity absorption component in V906 Car, and the duration of the commencement of the main H α emission. We constrain the time taken for V5668 Sgr to transition to the nebular phase using [N ii] 6584 Å. We find these timings to be consistent with the jet and accretion disc model for explaining optical spectral line profile changes in classical novae, and discuss the implications of this model for enrichment of the interstellar medium.