Diffuse interstellar band from the spectrum of auto-ionizing helium

Abstract

© 2020 SPIE. We explore the possibility of using transition energies of a doubly excited helium atom to describe the absorption lines of interstellar medium. We follow the method of approximated separation of variables in hypersperical coordinate in solving the energy levels of doubly excited helium. Although the results do not exactly match with the absorption spectrum of the diffuse interstellar bands, they show some correlation. We have also shown that the distribution of the difference between observed spectrum and the calculated result can be fit by normal distribution with the mean value close to zero. Furthermore, we argued that the distribution obtained from randomly generated lines are significantly different from the calculated result.