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Bright Rims in Diffuse Nebulae

Published online by Cambridge University Press:  03 August 2017

Stuart R. Pottasch
Stuart R. Pottasch*
Affiliation:
National Bureau of Standards, Boulder, Colorado

Extract

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Bright rims at the edge of dark markings associated with diffuse nebulae have been noticed for more than thirty years. An example is shown in Fig. 1, a photographic negative of the diffuse nebula IC 1396. Figure 1(a) shows the entire nebula, which is excited by an O6 star (circled). Figure 1(b) is an enlargement of one of the bright rims in this nebula. A number of general characteristics can be pointed out. The bright rim is always at the edge of what appears to be dark matter and always is bright on that side of the matter closest to the exciting star. If a line of symmetry is drawn through the dark material it is found in general to pass very near to the exciting star. Sometimes isolated matter similar to Bok's globules are present, and when present also show bright rims. These globules are included in the observational study.

Type
Part VI: Conditions at the Ionization and Shock Fronts in Collisions of Gas Clouds
Information
Symposium - International Astronomical Union , Volume 8: Cosmical Gas Dynamics , July 1958 , pp. 1053 - 1058
Copyright
Copyright © American Physical Society 1958 

References

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