Post–Asymptotic Giant Branch Evolution in the Large Magellanic Cloud: A Study of the Central Stars of Planetary Nebulae

We present medium- and broad-band Hubble Space Telescope (HST) photometry ofa sample of 35 central stars (CSs) of Planetary Nebulae (PNs) in the LargeMagellanic Cloud (LMC). The observations were made with the WFPC2 and STISinstruments on board the HST. By observing LMC objects, our sample is free ofthe distance uncertainty that is the dominate source of error in thedetermination of CS luminosities in Galactic PNs. By observing with the HST, weresolve the nebula and therefore we often detect the CSs unambiguously. Weobtain core masses of 16 of the objects by comparing their positions on the HRdiagram to theoretical evolutionary tracks, once we determine the stellareffective temperature through Zanstra analysis. This sample of CS masses is thelargest and most reliable set obtained in an extra-Galactic environment. Wefind an average mass of 0.65 Msun, though a few of the objects have very highmass. This average value is consistent with the average mass of the white dwarfpopulation in the Galaxy. As the immediate precursors of white dwarfs, thestudy of the mass distribution of PN CSs should help to constrain theinitial-to-final mass relation within environments of differing metallicity.Finally, by exploring the physical connections between the star and the nebula,we establish the importance of the study of PNs in the LMC to constrain theenergy input from the wind during the post-AGB phase.Comment: Accepted for publication in Astrophysical Journal. 23 pages, 8 figures and 4 table