Question

In general terms, explain how the O₂ line is likely produced and when is that line produced?. What wavelength are the molecular oxygen photons and why are they missing by the time the Sun’s light reaches the telescope?

Answer 1

The O2 line is a dark line in solar spectrum. This line is produced when solar radiation is absorbed by atmospheric oxygen. As a result the electron in the oxygen get excited to higher energy levels and subsequently comes down to the ground state by releasing electromagnetic radiation. The wavelengths of the photon corresponding to molecular oxygens are between 627 nm to 898 nm. We do not see these lines in the telescope because these wavelengths are get absorbed by earth's atmospheric oxygen before reaching to the telescope.