Formation of the UV spectrum of molecular hydrogen in the sun

Thus the majority of H-2 emission forms in a narrow region, at about 650 km in standard one-dimensional (1D) models of the quiet Sun, near the tau = 1 opacity surface for the exciting UV radiation, generally coming from above. When irradiated from above using observed intensities of bright UV emission lines, detailed non-LTE calculations show that the spectrum of H-2 seen in the quiet-Sun Solar Ultraviolet Measurement of Emitted Radiation atlas spectrum and HRTS light-bridge spectrum can be satisfactorily reproduced in 1D stratified atmospheres, without including three-dimensional or time-dependent thermal structures.

A detailed comparison to observations from 1205 to 1550 angstrom is presented, and the success of this 1D approach to modeling solar UV H-2 emission is illustrated by the identification of previously unidentified lines and upper levels in HRTS spectra.