The 3D non-LTE solar nitrogen abundance from atomic lines

• Nitrogen is an important element in various fields of stellar and Galactic astronomy, and the solar nitrogen abundance is crucial as a yardstick for comparing different objects in the cosmos. In order to obtain a precise and accurate value for this abundance, we carried out NI line formation calculations in a 3D radiative-hydrodynamicSTAGGER model solar atmosphere in full 3D non-local thermodynamic equilibrium (non-LTE). We used a model atom that includes physically motivated descriptions for the inelastic collisions of NI with free electrons and with neutral hydrogen. We selected five NI lines of high excitation energy to study in detail, based on their strengths and on their being relatively free of blends. We found that these lines are slightly strengthened from non-LTE photon losses and from 3D granulation effects, resulting in negative abundance corrections of around - 0.01 dex and - 0.04 dex, respectively. Our advocated solar nitrogen abundance is log (N) = 7.77, with the systematic 1 sigma uncertainty estimated to be 0.05 dex. This result is consistent with earlier studies after correcting for differences in line selections and equivalent widths.

Ämnesord

NATURVETENSKAP  -- Fysik -- Astronomi, astrofysik och kosmologi (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Astronomy, Astrophysics and Cosmology (hsv//eng)

Nyckelord

atomic processes

radiative transfer

line: formation

Sun: abundances

Sun: photosphere

stars: abundances

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