Eagle Nebula

Lore & Background

The Eagle Nebula was discovered by Jean-Philippe de Cheseaux in 1745–46. Both the "Eagle" and the "Star Queen" refer to visual impressions of the dark silhouette near the center of the nebula, an area made famous as the "Pillars of Creation" imaged by the Hubble Space Telescope. The nebula lies in the Sagittarius Arm of the Milky Way and contains several active star-forming gas and dust regions, including the Pillars of Creation.

The Eagle Nebula is a diffuse emission nebula, or H II region, catalogued as IC 4703. This region of active current star formation is about 5700 light-years distant. A spire of gas 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, mostly concentrated in a gap in the molecular cloud to the north-west of the Pillars. The brightest star, HD 168076, is a binary star with 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 name "Star Queen Nebula" was introduced by Robert Burnham Jr., reflecting his characterization of the central pillar as the Star Queen shown in silhouette.

Images produced by Jeff Hester and Paul Scowen using the Hubble Space Telescope in 1995 greatly improved scientific understanding of processes inside the nebula. One of these became famous as the "Pillars of Creation," depicting a large region of star formation. Its small dark pockets are believed to be protostars (Bok globules). The pillar structure resembles that of a much larger instance in the Soul Nebula of Cassiopeia. These columns 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 ("Evaporating Gaseous Globules"). Stars are being formed inside some of these. X-ray images from the Chandra Observatory compared with Hubble's "Pillars" image have shown that X-ray sources (from young stars) do not coincide with the pillars, but rather randomly dot the nebula.

Reader's Guide

The Eagle Nebula's significance stems largely from the "Pillars of Creation" region, imaged by the Hubble Space Telescope in 1995 by Jeff Hester and Paul Scowen. These images greatly improved scientific understanding of processes inside the nebula, revealing small dark pockets believed to be protostars (Bok globules) and denser gas knots called EGGs (Evaporating Gaseous Globules) where stars are forming. The pillars are composed of interstellar hydrogen gas and dust that act as incubators for new stars. Evidence from the Spitzer Space Telescope originally suggested the pillars may be threatened by a past supernova that exploded 8,000 to 9,000 years ago, with a shock wave possibly blowing them away. However, in 2014, Hubble imaged the pillars a second time in visible and infrared light, providing a detailed account of the rate of evaporation within them. No supernova was evidenced, and it is estimated the pillars will still exist for at least 100,000 more years. The nebula's legacy includes its iconic status in astronomy and its role in demonstrating active star formation processes.

Did You Know?

• The Eagle Nebula is also catalogued as Messier 16, M16, NGC 6611, and IC 4703.
• The spire of gas in the northeastern part of the nebula is approximately 9.5 light-years long.