AbstractPlanetary nebula luminosity functions provide very accurate distances to galaxies as judged by comparisons with other techniques, including Cepheids; systematic effects cannot be significant. The method is empirical and is a consequence of the shallow initial-final mass relationship predicted by stellar evolution and directly measured. From distances to ∼ 30 galaxies, the PNLF yields H0 = 79, in excellent agreement with recent Cepheid discoveries in Virgo.
Anchors for the cosmic distance scale: the Cepheids U Sagittarii, CF Cassiopeiae, and CEab Cassiopeiae
