Since I cannot directly fetch or open external PDF files, I’ll provide a that you can use to compare with or supplement your PDF (whether it’s a scientific paper, textbook chapter, or lecture slide labeled “306”).
The European Space Agency’s Gaia DR3 includes over 1.5 million white dwarf candidates. Search the Gaia archive for objects within 100 parsecs and filter by wd_best_class = 306 (if that classifier exists in your specific query). The resulting PDF will be a data certificate. white dwarf 306 pdf