The progenitor of the “born-again” core V605 Aql and the relation to its younger twin V4334 Sgr*
Institut für Astrophysik der Universität Innsbruck, Technikerstr. 25, 6020 Innsbruck, Austria e-mail: email@example.com
Accepted: 22 June 2004
We derived the properties of V605 Aql before the final helium flash pulse by studying its surrounding PN A58. Photoionizing models of our spectral data together with a new distance estimate and a closer look at the recombination timescales lead to a consistent model. Comparing our findings with the only hydrogen-poor twin, namely Sakurai's Object, we conclude that these born-again objects have normal PNe core masses. We are able to prove V605 Aql indeed to be, similar to V4332 Sgr, a very late thermal pulse object and to put constraints on the evolutionary time scales for the transition back to the AGB.
Key words: stars: AGB and post-AGB / stars: evolution / ISM: planetary nebulae: individual: Abell 58 / stars: individual: V605 Aql, V4334 Sgr
© ESO, 2004