astronomy

Eagle Nebula

Eagle Nebula is a astronomy topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Eagle Nebula rather than just read about it. In short: The Eagle Nebula is a young open cluster of stars in the constellation of Serpens. Alternatively, it is catalogued as Messier 16, M16, or NGC 6611, and sometimes referred to as the Star Queen Nebula.

Key takeaways

Eagle Nebula belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Eagle Nebula to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Eagle Nebula from memory before moving on to harder problems.

Reference excerpt

The Eagle Nebula is a young open cluster of stars in the constellation of Serpens. Alternatively, it is catalogued as Messier 16, M16, or NGC 6611, and sometimes referred to as the Star Queen Nebula. This cluster 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 contains several active star-forming gas and dust regions, including the aforementioned Pillars of Creation. The Eagle Nebula lies in the Sagittarius Arm of the Milky Way.

Characteristics

The Eagle Nebula is 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 (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.

"Pillars of Creation" region

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, imaged with the Spitzer Space Telescope in 2005 equally 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. 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. Any protostars in the pillars' EGGs are not yet hot enough to emit X-rays.

Possible annihilation via supernova Evidence from the Spitzer Space Telescope originally suggested that the pillars in M16 may be threatened by a "past supernova". Hot gas observed by Spitzer in 2007 suggested they were already – likely – being disturbed by a supernova that exploded 8,000 to 9,000 years ago. Due to the distance the main blast of light would have reached Earth for a brief time 1,000 to 2,000 years ago. A more slowly moving, theorized, shock wave 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 images being 20 years later provided a new, detailed account of the rate of evaporation occurring within the pillars. No supernova is evidenced within them, and it is estimated in some form they still exist – and will appear for at least 100,000 more years.

See also List of Messier objects NGC 1193

References

Further reading The Belt of Venus. M16 and IC 4703 - The Eagle Nebula. 9/12/07. The Belt of Venus

External links

The Eagle Nebula on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images The Eagle's EGGs – ESO Photo Release ESO: An Eagle of Cosmic Proportions incl. Photos & Animations ESO: VST Captures Three-In-One incl. Photos & Animations Messier 16, SEDS Messier pages Spacetelescope.org, Hubble telescope images on M16 Darkatmospheres.com, Eagle Nebula M16 (wide) NASA.gov, APOD February 8, 2009 picture Eagle Nebula Szymanek, Nik; Lawrence, Pete; Crowther, Paul; Merrifield, Michael. "M16 – Eagle Nebula". Deep Sky Videos. Brady Haran. Eagle Nebula (Messier 16) at Constellation Guide

Illustrations

Worked examples

Example 1 — a first encounter with Eagle Nebula

Start with the simplest possible case. Write down what Eagle Nebula claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In astronomy, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Eagle Nebula before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Eagle Nebula ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Eagle Nebula

In research: Eagle Nebula appears in astronomy research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Eagle Nebula in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Eagle Nebula is common in secondary-school and first-year university syllabi. It links to neighbouring topics Astronomical objects discovered in 1745, Carina–Sagittarius Arm, Gum Catalogue, so understanding it makes those chapters shorter.
In everyday life: Look for Eagle Nebula outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Eagle Nebula in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Eagle Nebula means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Eagle Nebula out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Eagle Nebula in simple terms?

The Eagle Nebula is a young open cluster of stars in the constellation of Serpens. Alternatively, it is catalogued as Messier 16, M16, or NGC 6611, and sometimes referred to as the Star Queen Nebula.

Why does Eagle Nebula matter?

Because it connects several astronomy ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Eagle Nebula?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Eagle Nebula.