1998A&A...340L..15P

We present the first unambiguous detection of the OV 1213.9Å (2s^{2 1}S₀ -> 2s2p ³P₂) forbidden line in the solar spectrum, using observations obtained with the SUMER instrument on board SOHO. The wavelength separation of the forbidden to the (2s^{2 1}S₀ -> 2s2p ³P₁) intercombination line at 1218.35Å is 4.5±0.1Å in excellent agreement with theoretical predictions. The observed line ratio, combined with the latest calculations, allows us to derive an electron density of logN_e/cm^–3=8.5±0.15 for the quiet Sun. However, the OV 1213.9Å line was not detected in the HST spectra of Procyon and we can only place a lower limit of logN_e/cm^–3≥7.8 to the electron density in this object.