The Solar Argon Abundance

The solar argon abundance cannot be directly derived by spectroscopic observations of the solar photosphere. The solar argon abundance is evaluated from solar wind measurements, nucleosynthetic arguments, observations of B stars, H II regions, planetary nebulae, and noble gas abundances measured in Jupiter's atmosphere. These data lead to a recommended argon abundance of N(Ar) = 91,200 +/- 23,700 (on a scale where Si = 10⁶ atoms). The recommended abundance for the solar photosphere [on a scale where log N(H) = 12] is A(Ar)_photo = 6.50 +/- 0.10, and taking element settling into account, the solar system (protosolar) abundance is A(Ar)_solsys = 6.57 +/- 0.10.