Physical Sciences and Mathematics Commons^™

Physical Conditions In Barnard's Loop, Components Of The Orion-Eridanus Bubble, And Implications For The Warm Ionized Medium Component Of The Interstellar Medium, C. R. O'Dell, Gary J. Ferland, R. L. Porter, P. A. M. Vanhoof

Physics and Astronomy Faculty Publications

We have supplemented existing spectra of Barnard's Loop with high accuracy spectrophotometry of one new position. Cloudy photoionization models were calculated for a variety of ionization parameters and stellar temperatures and compared with the observations. After testing the procedure with recent observations of M43, we establish that Barnard's Loop is photoionized by four candidate ionizing stars, but agreement between the models and observations is only possible if Barnard's Loop is enhanced in heavy elements by about a factor of 1.4. Barnard's Loop is very similar in properties to the brightest components of the Orion-Eridanus Bubble and the warm ionized medium …