astronomy

NGC 4147

NGC 4147 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 4147 rather than just read about it. In short: NGC 4147 is the New General Catalogue identifier for a globular cluster of stars in the northern constellation of Coma Berenices. It was discovered by English astronomer William Herschel on March 14, 1784, who described it as "very bright, pretty large, gradually brighter in the middle".

Key takeaways

NGC 4147 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 4147 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of NGC 4147 from memory before moving on to harder problems.

Reference excerpt

NGC 4147 is the New General Catalogue identifier for a globular cluster of stars in the northern constellation of Coma Berenices. It was discovered by English astronomer William Herschel on March 14, 1784, who described it as "very bright, pretty large, gradually brighter in the middle". With an apparent visual magnitude of 10.7, it is located around 60,000 light years away from the Sun at a relatively high galactic latitude of 77.2°. This is a relatively small globular cluster, ranking 112th in luminosity among the Milky Way globular cluster population. It is considered an Oosterhoff type I cluster (OoI), despite having a relatively low metallicity. Indeed, it has the lowest metallicity of any OoI cluster known. There are 19 RR Lyrae variable star candidates and as many as 23 blue stragglers. A high proportion of the latter are concentrated near the dense core of the cluster, which is consistent with the idea that blue stragglers form through stellar mergers. The cluster lies some 70.4 ± 7.5 kly (21.6 ± 2.3 kpc) from the Galactic Center, and is relatively isolated from other globular clusters in the galaxy. The position of this cluster makes it a candidate for association with the Sagittarius tidal stream, and thus it may have been captured by the Milky Way after separation from the Sagittarius Dwarf Spheroidal Galaxy. A contour map of the cluster appears to show S-shaped tidal arms stretching to the north and south for several tidal radii. Such features are predicted for globular clusters that follow elliptical orbits and are near their apogalacticon.

References

External links Media related to NGC 4147 at Wikimedia Commons

Illustrations

Worked examples

Example 1 — a first encounter with NGC 4147

Start with the simplest possible case. Write down what NGC 4147 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 4147 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 4147 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 4147

In research: NGC 4147 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 4147 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 4147 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Astronomical objects discovered in 1784, Coma Berenices, Globular clusters, so understanding it makes those chapters shorter.
In everyday life: Look for NGC 4147 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 4147 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what NGC 4147 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 4147 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is NGC 4147 in simple terms?

Why does NGC 4147 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 4147?

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 4147.