AAO image reference AAT 38. « Previous || Next »
Top left is NE. Image width is about 41 arc min
Image and text © 1984-2010, Australian Astronomical Observatory, photograph by David Malin.
These two star-formation regions appear side by side in Carina and seem to be linked as parts of an extensive nebula. However, the apparent intimacy is a line-of-sight effect because these two objects are at quite different distances from the Sun. The curious looped nebula NGC 3576 is about 7000 light years from us while its neighbour NGC 3603 is more than twice as far away. That NGC 3603 is the more distant is confirmed by its colour, which is a ruddier red than the pinkish hue of NGC 3576. The change in colour is due to absorption of the blue-light component of the nebulosity by dust particles in the much longer line of sight. This effect is known as interstellar reddening, though it would be better described as 'de-blueing'. It is also seen in the Horsehead nebula.
Related Images
AAT 38a. NGC 3576 and NGC 3603 (wide field view)
AAT 39. The loops of NGC 3576
AAT 40. Reddened nebulosity in NGC 3603
Constellation of Carina (external site)
For details of photographic exposure, search technical table by AAT reference number.