000002123 001__ 2123
000002123 005__ 20160706150359.0
000002123 0247_ $$2DOI$$a10.1051/0004-6361/201423629
000002123 037__ $$aASTROimport-280
000002123 100__ $$aHajduk, M.
000002123 245__ $$aEvolution of the central stars of young planetary nebulae
000002123 260__ $$c2015
000002123 520__ $$aAims: The evolution of central stars of planetary nebulae was so far documented in just a few cases. However, spectra collected a few decades ago may provide a good reference for studying the evolution of central stars using the emission line fluxes of their nebulae. We investigated evolutionary changes of the [O iii] 5007 Å line flux in the spectra of planetary nebulae.  Methods: We compared nebular fluxes collected during a decade or longer. We used literature data and newly obtained spectra. A grid of cloudy models was computed using existing evolutionary models, and the models were compared with the observations.  Results: An increase of the [O iii] 5007 Å line flux is frequently observed in young planetary nebulae hosting H-rich central stars. The increasing nebular excitation is the response to the increasing temperature and hardening radiation of the central stars. We did not observe any changes in the nebular fluxes in the planetary nebulae hosting late-type Wolf-Rayet (WR) central stars. This may indicate a slower temperature evolution (which may stem from a different evolutionary status) of late-[WR] stars.  Conclusions: In young planetary nebulae with H-rich central stars, the evolution can be followed using optical spectra collected during a decade or longer. The observed evolution of H-rich central stars is consistent with the predictions of the evolutionary models provided in the literature. Late-[WR] stars possibly follow a different evolutionary path. Reduced spectra from the Torun and SAAO observatories are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr ( or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/573/A65
000002123 700__ $$avan Hoof, P. A. M.
000002123 700__ $$aZijlstra, A. A.
000002123 773__ $$cA65$$pAstronomy and Astrophysics$$v573$$y2015
000002123 85642 $$ahttp://esoads.eso.org/abs/2015A%26A...573A..65H
000002123 905__ $$apublished in
000002123 980__ $$aREFERD