Observations of planetary nebulae have revealed unusual molecular content and surprising enrichments of rare isotopes, challenging both chemical models as well as our current understanding of stellar nucleosynthesis.
![](https://scx1.b-cdn.net/csz/news/tmb/2019/4-stars.jpg)
Source:
https://phys.org/news/2020-06-unusual-molecular-isotopic-content-planetary.html