Figure 1.
Plot of the theoretical [Cl iii] nebular emission line ratio R1 = I(3s23p3 4S–3s23p3 2D5/2)/I(3s23p3 4S–3s23p3 2D3/2) = I(5518 Å)/I(5538 Å) against the auroral/nebular ratio R2 = I(3s23p3 2D3/2–3s23p3 2P3/2)/I(3s23p3 4S–3s23p3 2D3/2,5/2) = I(8434 Å)/I(5518 + 5538 Å), where I is in energy units, for a range of electron temperatures (Te = 5,000–20,000 K in steps of 2,500 K) and logarithmic electron densities (log Ne = 1.5–5.5 in steps of 0.5 dex; Ne in cm−3). Points of constant Te are connected by solid lines, whereas those of constant Ne are joined by dashed lines.