astronomy

NGC 3489

NGC 3489 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 3489 rather than just read about it. In short: NGC 3489 is a lenticular galaxy located in the constellation Leo. It is located at a distance of about 30 million light years from Earth, which, given its apparent dimensions, means that NGC 3489 is about 30,000 light years across.

Key takeaways

NGC 3489 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 3489 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of NGC 3489 from memory before moving on to harder problems.

Reference excerpt

NGC 3489 is a lenticular galaxy located in the constellation Leo. It is located at a distance of about 30 million light years from Earth, which, given its apparent dimensions, means that NGC 3489 is about 30,000 light years across. It was discovered by William Herschel on April 8, 1784. NGC 3489 is a member of the Leo Group. NGC 3489 has a weak bar, seen along the minor axis, and a small bulge. The age of the stellar population in NGC 3489 shows a gradient, with the younger stars lying closer to the core. When observed in H-beta, the central arcsecond of NGC 3489 shows a peak, indicating the presence of younger stars at the core, whose age is estimated to be about 1.7 Gys. Although currently NGC 3489 is considered a post-starburst galaxy, there is still molecular gas in the nucleus that can lead to star formation, although its mass is less than what is found in galaxies with active star formation. In the nuclear region of NGC 3489 has been observed dust with an open spiral pattern. The galaxy has an outer ring structure, with a diameter of 1.54 arcminutes along the major axis. NGC 3489 has an active galactic nucleus, which has been categorised based on its spectrum as a type 2 Seyfert galaxy or, based on the nuclear [O I] emission strength, which lies between that of H II nuclei and LINER, a transition object. This kind of transition emission could be attributed to post AGB stars located in the core. A supermassive black hole which accretes material in the centre of the galaxy is believed to be the cause of nuclear activity. In the centre of NGC 3489 lies a black hole with estimated mass (6±0.54)×106 M☉ based on velocity dispersion.

Gallery

References

External links

NGC 3489 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images NGC 3489 on SIMBAD

Illustrations

Worked examples

Example 1 — a first encounter with NGC 3489

Start with the simplest possible case. Write down what NGC 3489 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 3489 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 3489 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 3489

In research: NGC 3489 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 3489 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 3489 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Astronomical objects discovered in 1784, Discoveries by William Herschel, Lenticular galaxies, so understanding it makes those chapters shorter.
In everyday life: Look for NGC 3489 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 3489 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what NGC 3489 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 3489 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is NGC 3489 in simple terms?

Why does NGC 3489 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 3489?

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 3489.