Constraints on stellar evolution by observation of white dwarfs

The recent observation of white dwarfs in the open cluster NGC 2516 and the determination of their surface gravity and effective temperatures (Reimers and Koester, 1982) has enabled the establishment of the initial-final mass relation for low and intermediate mass stars which was published a few months ago and is presented here (Fig. 1 of Weidemann and Koester, 1983a). The most important conclusions drawn are: 1. The limiting mass for white dwarf progenitors is 8–9 M ⊙ rather than 5–6 M ⊙ , with supernova production beyond; 2. The rather flat run of the initial-final mass relation in the main range of star production, 1–5 M ⊙ , explains the observed narrow mass distribution of white dwarfs and central stars of planetary nebulae around 0.6 M ⊙ ; 3. High mass white dwarfs exist, as shown in the rich, young cluster NGC 2516, but are extremely rare in general.