Backscattering and Line Broadening in Orion

C. R. O’Dell, G. J. Ferland, J. E. Méndez-Delgado

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


Examination of emission lines in high-velocity-resolution optical spectra of the Orion Nebula confirms that the velocity component on the red wing of the main ionization front emission line is due to backscattering in the Photon Dominated Region. This scattered light component has a weak wavelength dependence that is consistent with either general interstellar medium particles or particles in the foreground of the Orion Nebula Cluster. An anomalous line-broadening component that has been known for 60+ years is characterized in unprecedented detail. Although this extra broadening may be due to turbulence along the line of sight of our spectra, we explore the possibility that it is due to Alfvén waves in conditions where the ratio of magnetic and thermal energies are about equal and constant throughout the ionized gas.

Original languageEnglish
Article number21
JournalAstronomical Journal
Issue number1
StatePublished - Jan 1 2023

Bibliographical note

Publisher Copyright:
© 2022. The Author(s). Published by the American Astronomical Society.

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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