Cometary globules are isolated, relatively small clouds of gas and dust within the Milky Way. This example in the constellation of Puppis is called CG4, it is about 1,300 light-years from Earth. Its head is some 1.5 light-years in diameter, and its tail is about eight light-years long. Such globules are frequently the birthplaces of stars, and are showing very young stars in their heads.
The head of the nebula is opaque, but glows because it is illuminated by light from nearby hot stars. Their energy is gradually destroying the dusty head of the globule, sweeping away the tiny particles which scatter the starlight. The globule shows a faint red glow from electrically charged hydrogen, and it seems about to devour an edge-on spiral galaxy (ESO 257-19) in the left side. In reality, this galaxy is more than a hundred million light-years further away, far beyond CG4.
Find a high resolution and very deep image taken with the 4 m Blanco telescope at CTIO here.
LHaRGB (L 20x20m, Ha 9x40m, R 7x20m, G 7x20m, B 7x20m) total 20 h combined. Seeing 0.7-1 arcsec
Processing: Johannes Schedler
80cm f/7 Astrooptik Keller corrected cassegrain, FLI Proline 16803, Baader Filters, Prompt 7 CTIO Chile
Find a HaLRGB image in 25/80% size below