Details: The Trifid Nebula was discovered by Charles Messier on June 5, 1764, and is number 20 in his catalog commonly shorthanded as M20.  Messier described it as a cluster of stars enveloped in nebulosity. It was named the Trifid by William Herschel in 1862 due to its three-part structure.

The Trifid Nebula is located over 4000 light years from Earth, and is over 40 light-years in sized. What powers the Trifid is its central massive star, HD 164492A, a class O7 blue star with a mass of over 20 of our suns! This star dominates the entire region creating powerful radiation as well as stellar winds. While resulting in a beautiful object in our night sky, the destructive forces of the winds and radiation may prevent many new stars from forming and destroy those already in the embryonic stage.

Due to the presence of so many types of objects, the Trifid has been an intense focus of investigations by astronomers both ground-based and space-based including the Hubble Telescope. Hubble images taken with special hydrogen, sulfur, and oxygen filters yielded an image that not only approached how humans might see it up close, but also showed detail about the stellar nursery. One important detail is the presence of a vast nursery of more than 30 embryonic stars and 120 new born stars visible only in infrared light. Both stellar jets and evaporating gas globules or EGGS can also be seen in the above image. These are likely the presence of newly forming stars; however, it is likely that the massive central star will cause these stars to eventually be eroded by the strong winds and radiation. Several of the jets visible are over a light-year long.

Annotations. In the image above, hover a mouse or curser over the image to show annotations of the Trifid Nebula, with several enlarged insets identifying interesting features! The bright red nebula on the right is the emission nebula. The bluish region on the left is the reflection nebula. Within the red emission nebula is the dark nebula, Barnard 85. Two embryonic jets and a globule are visible in the inset to the far right. Middle insets show close up views of the dark nebula and far lower right is a evaporating gas globule within the reflection nebula. Below Images: In the first image below, the same image as above, has been processed to remove all stars, except for the central star. This is what the view would appear like if no stars existed along our line of sight. Using a mouse to hover over the image brings all the stars back. The second image below shows an enlarged and cropped version of the Bubble Nebula; this time hovering a mouse makes the stars disappear. The final image below is the same data but using old generation 2 processing techniques versus today’s newer generation 4. Hovering the mouse over this image reveals a direct comparison of old and new images. Note how tighter the stars are and how the nebula is more visible with more detail than before.

Object Statistics: Constellation: Sagittarius, Right Ascension: 18h 02m 23s, Declination: -23° 01' 48”, Magnitude: 6.3, Size: 28’ x 25', Distance 4100 light-years and over 40 light-years across.