astronomy

NGC 7321

NGC 7321 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 NGC 7321 rather than just read about it. In short: NGC 7321 is a barred spiral galaxy in the constellation of Pegasus. Its velocity with respect to the cosmic microwave background is 6,793±25 km/s, which corresponds to a Hubble distance of 326.8 ± 22.9 Mly (100.19 ± 7.02 Mpc).

Key takeaways

NGC 7321 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect NGC 7321 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of NGC 7321 from memory before moving on to harder problems.

Reference excerpt

NGC 7321 is a barred spiral galaxy in the constellation of Pegasus. Its velocity with respect to the cosmic microwave background is 6,793±25 km/s, which corresponds to a Hubble distance of 326.8 ± 22.9 Mly (100.19 ± 7.02 Mpc). However, seven non-redshift measurements give a closer mean distance of 297.50 ± 14.14 Mly (91.214 ± 4.334 Mpc). It was discovered by German-British astronomer William Herschel on 17 November 1784. NGC 7321 is a LINER galaxy, i.e. a galaxy whose nucleus has an emission spectrum characterized by broad lines of weakly ionized atoms.

Galaxy group According to M. J. Geller and J. P. Huchra, NGC 7321 is a member of a galaxy group which contains 2 other galaxies: NGC 7316 and NGC 7323.

Supernovae Two supernovae have been observed in NGC 7321:

SN 2008gj (Type Ic, mag. 18.2) was discovered by the Lick Observatory Supernova Search (LOSS) on 19 October 2008. SN 2013di (Type Ia, mag. 18.2) was discovered by the Catalina Real-time Transient Survey on 12 June 2013.

See also List of NGC objects (7001–7840)

References

External links Media related to NGC 7321 at Wikimedia Commons NGC 7321 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images

Illustrations

Worked examples

Example 1 — a first encounter with NGC 7321

Start with the simplest possible case. Write down what NGC 7321 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 NGC 7321 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 NGC 7321 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 NGC 7321

In research: NGC 7321 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 NGC 7321 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: NGC 7321 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Astronomical objects discovered in 1784, Barred spiral galaxies, Discoveries by William Herschel, so understanding it makes those chapters shorter.
In everyday life: Look for NGC 7321 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 NGC 7321 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what NGC 7321 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 NGC 7321 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is NGC 7321 in simple terms?

Why does NGC 7321 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 NGC 7321?

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 NGC 7321.