The Eagle Nebula is part of a diffuse emission nebula, or H II region, which is catalogued as IC 4703. This region of active current star formation is about 5700 light-years distant. A spire of gas that can be seen coming off the nebula in the northeastern part is approximately 9.5 light-years or about 90 trillion kilometers long. The cluster associated with the nebula has approximately 8100 stars, which are mostly concentrated in a gap in the molecular cloud to the north-west of the Pillars. The brightest star has an apparent magnitude of +8.24, easily visible with good binoculars. It is actually a binary star formed of an O3.5V star plus an O7.5V companion. This star has a mass of roughly 80 solar masses, and a luminosity up to 1 million times that of the Sun. The cluster's age has been estimated to be 1–2 million years. The descriptive names reflect impressions of the shape of the central pillar rising from the southeast into the central luminous area. The name "Star Queen Nebula" was introduced by Robert Burnham, Jr., reflecting his characterization of the central pillar as the Star Queen shown in silhouette.
"Pillars of Creation" region
Images taken by Jeff Hester and Paul Scowen using the HubbleSpace Telescope in 1995 greatly improved scientific understanding of processes inside the nebula. One of these photographs became famous as the "Pillars of Creation", depicting a large region of star formation. The small dark areas in the photograph are believed to be protostars. The pillar structure of the region resembles that of a much larger star formation region in the Soul Nebula of Cassiopeia, imaged with the Spitzer Space Telescope in 2005 and characterized as "Pillars of Star Creation". or "Pillars of Star Formation". These columns – which resemble stalagmites protruding from the floor of a cavern – are composed of interstellar hydrogen gas and dust, which act as incubators for new stars. Inside the columns and on their surface astronomers have found knots or globules of denser gas, called EGGs. Stars are being formed inside some of these EGGs. X-ray images from the Chandra observatory compared with Hubble's "Pillars" image have shown that X-ray sources do not coincide with the pillars, but instead randomly dot the area. Any protostars in the pillars' EGGs are not yet hot enough to emit X-rays. Evidence from the Spitzer Telescope originally suggested that the pillars in M16 may already have been destroyed by a supernova explosion. Hot gas observed by Spitzer in 2007 suggested that the area was disturbed by a supernova that exploded some 8,000 to 9,000 years ago. Due to the distance of the nebula, the light from the supernova would have reached Earth between 1,000 and 2,000 years ago. The more slowly moving shock wave from the supernova would have taken a few thousand years to move through the nebula and would have blown away the delicate pillars. However, in 2014 the Pillars were imaged a second time by Hubble, in both visible light and infrared light. The new images being 20 years apart provided a new, detailed account of the rate of evaporation occurring within the pillars. It was later discovered that there in fact was no supernova explosion within them, and it is estimated they will be around for at least 100,000 years longer.
