The Initial-Final Mass Relation

It is well known that the stellar life cycle is dominated by queiscent phases such as the hydrogen-burning stage and the eventual remnant white dwarf cooling phase. However, between these two stages, stars dramatically transform themselves by losing the bulk of their mass. Planetary nebulae provide a powerful clue to the physical processes involved in this transformation, however, our understanding of the detailed phasing, dependency to metallicity and other properties, and total amount of the source mass loss is still highly uncertain. Over the past 10 years, a new wave of space- and ground-based imaging and spectroscopy programs have uncovered the remnants of the planetary nebula evolutionary stage, white dwarfs, in a wide range of well measured environments. With knowledge of the host stellar population properties (e.g., ages of star clusters), we can map the masses and temperatures of the stellar remnants to the properties of their progenitors. This work has now led to the first global mapping of the initial-final mass relation from 0.8 Msun to 6 Msun. The resulting relation is a fundamental input into our understanding of the stellar evolution process for low and intermediate-mass stars that produce planetary nebulae and has a wide range of applications to interpret stellar populations in distant galaxies.