astronomy

NGC 4689

NGC 4689 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 4689 rather than just read about it. In short: NGC 4689 is a spiral galaxy located about 54 million light-years away in the constellation of Coma Berenices. NGC 4689 is also classified as a LINER galaxy.

Key takeaways

NGC 4689 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 4689 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of NGC 4689 from memory before moving on to harder problems.

Reference excerpt

NGC 4689 is a spiral galaxy located about 54 million light-years away in the constellation of Coma Berenices. NGC 4689 is also classified as a LINER galaxy. NGC 4689 is inclined at an angle of about 36° which means that the galaxy is seen almost face-on to the Earth's line of sight. NGC 4689 was discovered by astronomer William Herschel on April 12, 1784. The galaxy is a member of the Virgo Cluster.

Physical characteristics NGC 4689 has ring-like feature in its inner regions. Surrounding the inner ring lies a zone of bright, flocculent spiral structure with a ring-like boundary. Outside this zone is a well-defined, diffuse outer ring which is an unusual feature for a late-type galaxy like NGC 4689.

Star formation The star forming disk in NGC 4689 has been truncated which means that the amount of star formation has been reduced significantly. This truncation may have been caused by an interaction with intracluster medium of the Virgo Cluster causing the galaxy to lose much of its interstellar medium in an effect known as ram-pressure stripping. Due to its reduced amount of star formation, NGC 4689 has been classified as an anemic galaxy.

Gallery

See also List of NGC objects (4001–5000) NGC 4921- an Anemic spiral galaxy in the Coma Cluster Messier 90 - another Anemic spiral galaxy in the Virgo Cluster

References

External links

NGC 4689 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 4689

Start with the simplest possible case. Write down what NGC 4689 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 4689 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 4689 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 4689

In research: NGC 4689 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 4689 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 4689 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Astronomical objects discovered in 1784, Coma Berenices, Flocculent spiral galaxies, so understanding it makes those chapters shorter.
In everyday life: Look for NGC 4689 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 4689 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what NGC 4689 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 4689 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is NGC 4689 in simple terms?

NGC 4689 is a spiral galaxy located about 54 million light-years away in the constellation of Coma Berenices. NGC 4689 is also classified as a LINER galaxy.

Why does NGC 4689 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 4689?

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 4689.