The Eagle Nebula (catalogued as Messier 16 or M16, and as NGC 6611, and also known as the Star Queen Nebula and The Spire) is a young open cluster of stars in the constellation Serpens, discovered by Jean-Philippe de Chéseaux 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 contains several active star-forming gas and dust regions, including the aforementioned Pillars of Creation.
|H II region|
Three-colour composite mosaic image of the Eagle Nebula, with north at top. Credit: ESO
|Observation data: J2000.0 epoch|
|Right ascension||18h 18m 48s|
|Distance||5,700±400 ly (1,740±130 pc)|
|Apparent magnitude (V)||+6.0|
|Apparent dimensions (V)||7.0 arcmins|
|Radius||70×55 (cluster 15) ly|
|Absolute magnitude (V)||-8.21|
|Notable features||1–2 million years old|
|Designations||Messier 16, NGC 6611, Sharpless 49, RCW 165, Gum 83, Star Queen Nebula|
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 7000 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 (HD 168076) 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.
Images taken 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 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 (Bok globules). 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 ("Evaporating Gaseous Globules"). 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 (from young stars) 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.
Elephant trunk (astronomy)
Elephant trunks (more formally, cold molecular pillars,) are a type of interstellar matter formations found in molecular clouds. They are located in the neighborhood of massive O type and B type stars, which, through their intense radiation, can create expanding regions of ionized gas known as H II regions. Elephant trunks resemble massive pillars or columns of gas and dust, but they come in various shapes, lengths, and colors. Astronomers study elephant trunks because of their unique formation process and use 2-D and 3-D simulations to try to understand how this phenomenon occurs.Embedded cluster
Embedded stellar clusters, or simply embedded clusters (EC), are open clusters that are still surrounded by their progenitor molecular cloud.
They are often areas of active star formation, giving rise to stellar objects that have similar ages and compositions.
Because of the dense material that surrounds the stars, they appear obscured in visible light but can be observed using other sections of the electromagnetic spectrum, such as the near-infrared and X-rays that can see through the cloud material. In our Galaxy, embedded clusters can mostly be found within the Galactic disk or near the Galactic center where most of the star-formation activity is happening. The sizes of stellar objects born in embedded clusters are distributed according to initial mass function, with many low-mass stars formed for every high-mass star. Nevertheless, the high-mass stars of temperature class O and B, which are significantly hotter and more luminous than the low-mass stars, have a disproportionate effect on their interstellar environment by ionizing the gas surrounding them creating H II regions. Many ultra-compact H II regions, the precursors to massive protostars, are associated with embedded clusters.Over time, radiation pressure from the stellar objects will disperse the molecular cloud and give rise to the better known open cluster.
Several famous embedded clusters include the Trapezium cluster in the Orion Nebula, L1688 in the Rho Ophiuchi cloud complex, NGC 2244 in the Rosette Nebula, the cluster in the Trifid Nebula, NGC 6611 in the Eagle Nebula, and Trumpler 14, 15, and 16 in the Carina NebulaEvaporating gaseous globule
An evaporating gas globule or EGG is a region of hydrogen gas in outer space approximately 100 astronomical units in size, such that gases shaded by it are shielded from ionizing UV rays. Dense areas of gas shielded by an evaporating gas globule can be conducive to the birth of stars. Evaporating gas globules were first conclusively identified via photographs taken by the Hubble Space Telescope in 1995.EGG's are the likely predecessors of new protostars. Inside an EGG the gas and dust are denser than in the surrounding dust cloud. Gravity pulls the cloud even more tightly together as the EGG continues to draw in material from its surroundings. As the cloud density builds up the globule becomes hotter under the weight of the outer layers, a protostar is formed inside the EGG.
A protostar may have too little mass to become a star. If so it becomes a brown dwarf. If the protostar has sufficient mass, the density reaches a critical level where the temperature exceeds 10 million kelvin at its center. At this point, a nuclear reaction starts converting hydrogen to helium and releasing large amounts of energy. The protostar then becomes a star and joins the main sequence on the HR diagram.Gum catalog
The Gum catalog is an astronomical catalog of 84 emission nebulae in the southern sky. It was made by the Australian astronomer Colin Stanley Gum (1924-1960) at Mount Stromlo Observatory using wide field photography. Gum published his findings in 1955 in a study entitled A study of diffuse southern H-alpha nebulae which presented a catalog of 84 nebulae or nebular complexes. Similar catalogs include the Sharpless catalog and the RCW catalog, and many of the Gum objects are repeated in these other catalogs.
The Gum Nebula is named for Gum, who discovered it as Gum 12; it is an emission nebula that can be found in the southern constellations Vela and Puppis.IC 4703
IC 4703 is the diffuse emission nebula or HII region associated with Messier 16, which is actually a cluster of stars. It is the nebulous region surrounding Messier 16. These two objects make up the Eagle Nebula. They are relatively bright and are located in the constellation Serpens Cauda. This region contains the picturesque Pillars of Creation. This is an active star forming region 7,000 light years away. It is approximately magnitude 8. The cluster was discovered by De Cheseaux, but Messier later rediscovered it and remarked on its apparent nebulous appearance. The cluster is estimated to be 5.5 million years old, and the nebula would be a bit older. The nebula is about 55 x 70 light years. The Eagle Nebula lies in the Sagittarius Arm of the Milky Way.Invasion of the Spiders
Invasion of the Spiders: Remixed... and Unreleased Tracks is a two-disc compilation album by Space, released on 12 August 1997 on Gut Records. Disc one consists of several remixes by the group (mainly from their keyboard player Franny Griffiths, credited under the aliases Frannie Asprin) and other artists, whilst the second disc compiles tracks that have previously appeared as B-sides.
The album's sleeve makes reference to the Pillars of Creation, an iconic photograph taken by the Hubble Space Telescope in 1995 demonstrating a formation of stars in the Eagle Nebula.List of Hubble anniversary images
List of Hubble anniversary images is a list of images released to celebrate the Hubble Space Telescope anniversaries. They celebrate its "birthday" when it was launched into orbit on April 24, 1990 by the Space Shuttle with its crew.List of diffuse nebulae
Reflection nebulaNGC 6604
NGC 6604 is an open star cluster located 5500 light years away in the constellation of Serpens and is located about two degrees north of the Eagle Nebula .Nebula
A nebula (Latin for 'cloud' or 'fog'; pl. nebulae, nebulæ, or nebulas) is an interstellar cloud of dust, hydrogen, helium and other ionized gases. Originally, the term was used to describe any diffuse astronomical object, including galaxies beyond the Milky Way. The Andromeda Galaxy, for instance, was once referred to as the Andromeda Nebula (and spiral galaxies in general as "spiral nebulae") before the true nature of galaxies was confirmed in the early 20th century by Vesto Slipher, Edwin Hubble and others.
Most nebulae are of vast size; some are hundreds of light-years in diameter. A nebula that is barely visible to the human eye from Earth would appear larger, but no brighter, from close by. The Orion Nebula, the brightest nebula in the sky and occupying an area twice the diameter of the full Moon, can be viewed with the naked eye but was missed by early astronomers. Although denser than the space surrounding them, most nebulae are far less dense than any vacuum created on Earth – a nebular cloud the size of the Earth would have a total mass of only a few kilograms. Many nebulae are visible due to fluorescence caused by embedded hot stars, while others are so diffuse they can only be detected with long exposures and special filters. Some nebulae are variably illuminated by T Tauri variable stars.
Nebulae are often star-forming regions, such as in the "Pillars of Creation" in the Eagle Nebula. In these regions the formations of gas, dust, and other materials "clump" together to form denser regions, which attract further matter, and eventually will become dense enough to form stars. The remaining material is then believed to form planets and other planetary system objects.Nebulae in fiction
Nebulae, often being visually interesting astronomical objects, are frequently used as settings or backdrops for works of science fiction.Photoevaporation
Photoevaporation denotes the process where energetic radiation ionises gas and causes it to disperse away from the ionising source. This typically refers to an astrophysical context where ultraviolet radiation from hot stars acts on clouds of material such as molecular clouds, protoplanetary disks, or planetary atmospheres.Pillars of Creation
Pillars of Creation is a photograph taken by the Hubble Space Telescope of elephant trunks of interstellar gas and dust in the Eagle Nebula, specifically the Serpens constellation, some 6,500–7,000 light years from Earth. They are so named because the gas and dust are in the process of creating new stars, while also being eroded by the light from nearby stars that have recently formed. Taken on April 1, 1995, it was named one of the top ten photographs from Hubble by Space.com. The astronomers responsible for the photo were Jeff Hester and Paul Scowen from Arizona State University. The region was rephotographed by ESA's Herschel Space Observatory in 2011, and again by the Hubble in 2014 with a newer camera (see below).Serpens
Serpens ("the Serpent", Greek Ὄφις) is a constellation of the northern hemisphere. One of the 48 constellations listed by the 2nd-century astronomer Ptolemy, it remains one of the 88 modern constellations defined by the International Astronomical Union. It is unique among the modern constellations in being split into two non-contiguous parts, Serpens Caput (Serpent Head) to the west and Serpens Cauda (Serpent Tail) to the east. Between these two halves lies the constellation of Ophiuchus, the "Serpent-Bearer". In figurative representations, the body of the serpent is represented as passing behind Ophiuchus between Mu Serpentis in Serpens Caput and Nu Serpentis in Serpens Cauda.
The brightest star in Serpens is the red giant star Alpha Serpentis, or Unukalhai, in Serpens Caput, with an apparent magnitude of 2.63. Also located in Serpens Caput are the naked-eye globular cluster Messier 5 and the naked-eye variables R Serpentis and Tau4 Serpentis. Notable extragalactic objects include Seyfert's Sextet, one of the densest galaxy clusters known; Arp 220, the prototypical ultraluminous infrared galaxy; and Hoag's Object, the most famous of the very rare class of galaxies known as ring galaxies.
Part of the Milky Way's galactic plane passes through Serpens Cauda, which is therefore rich in galactic deep-sky objects, such as the Eagle Nebula (IC 4703) and its associated star cluster Messier 16. The nebula measures 70 light-years by 50 light-years and contains the Pillars of Creation, three dust clouds that became famous for the image taken by the Hubble Space Telescope. Other striking objects include the Red Square Nebula, one of the few objects in astronomy to take on a square shape; and Westerhout 40, a massive nearby star-forming region consisting of a molecular cloud and an H II region.Sh2-54
Sh2-54 is an extended bright nebula in the constellation of Serpens.In its core there are many protostars and many infrared sources; some of these sources, like IRAS 18151−1208, are most probably very young high-mass stars. The older star population in this region has an average age of 4-5 millions years, and its components are grouped in the open cluster NGC 6604.Sh2-54 belongs to an extended nebulosity that includes also the Eagle Nebula and the Omega Nebula. The young high-mass stars of this region constitute the Serpens OB1 and Serpens OB2 OB association.Shalabi Effect (album)
Shalabi Effect is the eponymous debut album of Shalabi Effect. The album cover is taken from the famous Eagle Nebula Pillars of Creation photo made by NASA's Hubble Space Telescope. The album began with the song "Aural Florida", which was originally going to be on a split release with Godspeed You! Black Emperor; when that release was abandoned, the rest of the album was created.The Best American Poetry 1999
The Best American Poetry 1999, a volume in The Best American Poetry series, was edited by David Lehman and by guest editor Robert Bly.Wide Field Camera 3
The Wide Field Camera 3 (WFC3) is the Hubble Space Telescope's last and most technologically advanced instrument to take images in the visible spectrum. It was installed as a replacement for the Wide Field and Planetary Camera 2 during the first spacewalk of Space Shuttle mission STS-125 (Hubble Space Telescope Servicing Mission 4) on May 14, 2009.
See also: Gum Nebula