The second death of Sakurai's Object (V4334 Sgr)

The discovery of Sakurai's Object, in 1996, provided the first modern observations of a very late thermal pulse. Models predicted that it would become a born-again planetary nebula over a few hundred years. It is however evolving very much faster: the first radio detection shows that ionization of the envelope has already started. To reproduce its unexpectedly fast evolution, we have developed a model in which convective mixing is strongly suppressed under the influence of flash burning. A strong prediction of this model is that the star will evolve back to very high temperatures at equally accelerated time scales. A CLOUDY photoionization model of the hydrogen-poor nebula indicates an ionized ejecta (carbon) mass of similar to 10(-3) M-circle dot, indicating that born-again objects may be significant contributors to carbonaceous dust in the galaxy.