astronomy

Owl Nebula

Owl 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 Owl Nebula rather than just read about it. In short: The Owl Nebula (also known as Messier 97, M97 or NGC 3587) is a planetary nebula approximately 2,030 light years away in the constellation Ursa Major. Estimated to be about 8,000 years old, it is approximately circular in cross-section with a faint internal structure.

Key takeaways

Owl 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 Owl Nebula to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Owl Nebula from memory before moving on to harder problems.

Reference excerpt

The Owl Nebula (also known as Messier 97, M97 or NGC 3587) is a planetary nebula approximately 2,030 light years away in the constellation Ursa Major. Estimated to be about 8,000 years old, it is approximately circular in cross-section with a faint internal structure. It was formed from the outflow of material from the stellar wind of the central star as it evolved along the asymptotic giant branch. The nebula is arranged in three concentric shells, with the outermost shell being about 20–30% larger than the inner shell. The owl-like appearance of the nebula is the result of an inner shell that is not circularly symmetric, but instead forms a barrel-like structure aligned at an angle of 45° to the line of sight. The nebula holds about 0.13 solar masses (M☉) of matter, including hydrogen, helium, nitrogen, oxygen, and sulfur; all with a density of less than 100 particles per cubic centimeter. Its outer radius is around 0.91 ly (0.28 pc) and it is expanding with velocities in the range of 27–39 km/s into the surrounding interstellar medium. The 14th magnitude central star has passed the turning point in its evolution and is condensing to form a white dwarf. It has 55–60% of solar mass, is 41 to 148 times solar luminosity (L☉), and has an effective temperature of 123,000 K. The star has been successfully resolved by the Spitzer Space Telescope as a point source that does not show the infrared excess characteristic of a circumstellar disk.

History The Owl Nebula was discovered by French astronomer Pierre Méchain on February 16, 1781. Pierre Méchain was Charles Messier's observing colleague, and the nebula was observed by Messier himself a few weeks following the initial sighting. Thus, the object was named Messier 97, and included in his catalog on March 24, 1781. Of the object, he noted:Nebula in the great Bear, near Beta: It is difficult to see, reports M. Méchain, especially when one illuminates the micrometer wires: its light is faint, without a star. M. Méchain saw it the first time on Feb 16, 1781, & the position is that given by him. Near this nebula he has seen another one, [the position of] which has not yet been determined [Messier 108], and also a third which is near Gamma of the Great Bear [Messier 109]. (diam. 2′).In 1844, Admiral William H. Smyth classified the object as a planetary nebula. When William Parsons, 3rd Earl of Rosse, observed the nebula in Ireland in 1848, his hand-drawn illustration resembled an owl's head. In his notes, the object was described as "Two stars considerably apart in the central region, dark penumbra round each spiral arrangement, with stars as apparent centres of attraction. Stars sparkling in it; resolvable." It has been known as the Owl Nebula ever since. More recent developments in the late 1900s include the discovery of a giant red halo of wind extended around its inner shells, and the mapping of the nebula's structure.

Observing Although the Owl Nebula can not be seen with the naked eye, a faint image of it can be observed under remarkably good conditions with a small telescope or 20×80 binoculars. To make out the nebula's more distinctive owl like eye features, a telescope with an aperture 10" or better is required. To locate the nebula in the night sky, look to the southwest corner of the Big Dipper's bowl, marked by the star Beta Ursae Majoris. From there, M97 lies just over 2.5 degrees in the southeast direction towards the star positioned opposite Beta Ursae Majoris in the other bottom corner of the Big Dippers Bowl, Gamma Ursae Majoris; which marks the constellations southwest corner. M97, together with Alpha Ursae Majoris, point the way to Polaris.

Gallery

See also Messier object List of Messier objects New General Catalogue List of planetary nebulae

References

External links

The Owl Nebula @ SEDS Messier pages The Owl Nebula at Calar Alto Observatory NightSkyInfo.com – M97, the Owl Nebula Archived 2009-05-20 at the Wayback Machine The Owl Nebula on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images Norton, Andy; Crowther, Paul; Hardy, Liam. "M97 – Owl Nebula". Deep Sky Videos. Brady Haran. The Owl Nebula (M97) at Constellation Guide Messier 97: Owl Nebula at Messier Objects

Illustrations

Worked examples

Example 1 — a first encounter with Owl Nebula

Start with the simplest possible case. Write down what Owl 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 Owl 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 Owl 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 Owl Nebula

In research: Owl 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 Owl 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: Owl Nebula is common in secondary-school and first-year university syllabi. It links to neighbouring topics Astronomical objects discovered in 1781, Discoveries by Pierre Méchain, Messier objects, so understanding it makes those chapters shorter.
In everyday life: Look for Owl 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 Owl Nebula in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Owl 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 Owl Nebula out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Owl Nebula in simple terms?

Why does Owl 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 Owl 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 Owl Nebula.