'Cometary' Globules and the Structure of the Gum Nebula

Tailed, comet-like objects found in the outskirts of the Gum nebula (and elsewhere) are shown to be $$\gt\,{10}^{5}$$ yr old. This implies that the H II region is much older than the Vela Pulsar 0833 – 45. Tailed structure found in NGC 5367 suggests the presence of ionized hydrogen falling into the galactic plane near l = 320°.