astronomy

NGC 5398

NGC 5398 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 5398 rather than just read about it. In short: NGC 5398 is a barred spiral galaxy in the southern constellation of Centaurus. It was discovered June 3, 1836 by John Herschel.

Key takeaways

NGC 5398 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 5398 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of NGC 5398 from memory before moving on to harder problems.

Reference excerpt

NGC 5398 is a barred spiral galaxy in the southern constellation of Centaurus. It was discovered June 3, 1836 by John Herschel. Distance estimates range from 5.39 Mpc to 18.30 Mpc. The tip of the red-giant branch method yields a distance of 11.6 Mpc, while the Tully–Fisher relation shows values of around 8.5 Mpc. It is receding with a heliocentric radial velocity of 1,219 km/s. The morphological class of NGC 5398 is SB(rs)dm, indicating this is a spiral galaxy with an inner bar (SB) and incomplete ring (rs) structures, plus broken, irregular spiral arms (dm). The galactic plane is inclined at an angle of 53° to the line of sight from the Earth. The oval outline of the disk has an angular size of 2.8′ × 1.7′ at a limiting magnitude of 25, with the major axis aligned along a position angle of 172°. At the southwestern end of the bar lies a giant H II region (GHR) designated Tol 89. It spans a region of 1.7 × 1.2 kpc with an absolute magnitude of −14.8 in the B (blue) band, making it "one of the most impressive GHRs known". This is the only large site in NGC 5398 that is undergoing star formation, and it suggests that NGC 5398 is engaged in some form of interaction.

See also NGC 4618 - a similar galaxy NGC 4625 - a similar galaxy

References

External links Media related to NGC 5398 at Wikimedia Commons GALEX page on NGC 5398

Illustrations

Worked examples

Example 1 — a first encounter with NGC 5398

Start with the simplest possible case. Write down what NGC 5398 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 5398 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 5398 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 5398

In research: NGC 5398 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 5398 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 5398 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Barred spiral galaxies, Centaurus, NGC objects, so understanding it makes those chapters shorter.
In everyday life: Look for NGC 5398 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 5398 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what NGC 5398 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 5398 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is NGC 5398 in simple terms?

NGC 5398 is a barred spiral galaxy in the southern constellation of Centaurus. It was discovered June 3, 1836 by John Herschel.

Why does NGC 5398 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 5398?

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 5398.