The Low‐ and Intermediate‐Mass Stellar Population in the Small Magellanic Cloud: The Central Stars of Planetary Nebulae

We present a study on the central stars (CSs) of Planetary Nebulae (PNe)observed in the Small Magellanic Cloud (SMC) with the Space Telescope ImagingSpectrograph instrument on-board the HST. The stellar magnitudes have beenmeasured using broad-band photometry, and Zanstra analysis of the nebulaeprovided the stellar temperatures. From the location of the CSs on the HRdiagram, and by comparing the observed CSs with current models of stellarevolution, we infer the CSs masses. We examine closely the possibility of lightcontamination in the bandpass from an unrecognized stellar companion, and weestablish strong constraints on the existence and nature of any binarycompanion. We find an average mass of 0.63 Msun, which is similar to the massobtained for a sample of CSs in the LMC (0.65 Msun). However, the SMC and LMCCS mass distributions differ slightly, the SMC sample lacking anintermediate-mass stellar population (0.65 to 0.75 Msun). We discuss thesignificance and possible reasons for the difference between the two massdistributions. In particular, we consider the differences in the star formationhistory between the clouds and the mass-loss rate dependence on metallicity.Comment: 30 pages, 6 figures, 5 tables. To be published in ApJ (October 20