5.3 a₀ (Bohr radius) is equal to 0.000000000000000000000000009089217346168369 pc (parsec). To convert from Bohr radius to parsec, multiply by 0.0000000000000000000000000017149466690883714 or divide by 583,108,511,783,388,800,000,000,000.
physical constant; the most probable distance between an electron and the nucleus in a nonrelativistic model of the hydrogen atom with infinitely heavy nucleus