A beautiful Trifid indeed! This is a splendid and incredibly beautiful RGB image, which also contains a lot of information.
Note the blue O-type star in the center of the Trifid which is responsible for powering the nebula. Note how dust close to the hot star reflects the predominantly blue light from this and a few other hot stars in a small cluster. Note how the nebula then changes color, first to soft pink, then to a much deeper magenta-red, and then back to blue again. Note that wisps of blue reflection nebulosity surrounds all of the Trifid Nebula instead of being located only to the north of the red nebula.
Also note that the bright blue reflection nebula seems to be illuminated by a bright yellow star! If that yellow star is the main source of light for the blue reflection nebula, then the yellow star and the blue nebula provide a most excellent example of how stars get reddened when much of their blue light is scattered away when their light is passing through a cloud. But the picture is also a splendid example of how this reflected light scatters back at observers at predominantly blue wavelengths. (Have you ever wondered why the Sun appears to be yellow when the sky is blue?
![Wink :wink:](./images/smilies/icon_wink.gif)
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Note how, at the interface of the red and the blue nebula, there is a large yellowish-white patch, which seems to reflect the true yellow-white color of the bright yellow star. But the white patch could be a mixture of light from several light-sources, including light from the blue star at the center of the red nebula.
Also note how there is a very large black patch of dust at the interface of the red and the blue nebula at three o'clock, and how the blue light that seeps through this dark dust has been reddened to a bluish-green hue.
Also note the bright blue star in the upper right part of the picture, at two o'clock. This is undoubtedly a very young, very hot star, which may have been formed out of gas that originally belonged to the same large cloud of gas and dust that has now produced the Trifid Nebula.
I want to thank both R Jay Gabany and the editors of this page for today's very beautiful APOD!
Ann