astronomy

NGC 4647

NGC 4647 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 4647 rather than just read about it. In short: NGC 4647 is an intermediate spiral galaxy estimated to be around 63 million light-years away in the constellation of Virgo. It was discovered by German-British astronomer William Herschel on March 15, 1784.

Key takeaways

NGC 4647 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 4647 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of NGC 4647 from memory before moving on to harder problems.

Reference excerpt

NGC 4647 is an intermediate spiral galaxy estimated to be around 63 million light-years away in the constellation of Virgo. It was discovered by German-British astronomer William Herschel on March 15, 1784. NGC 4647 is listed along with Messier 60 as being part of a pair of galaxies called Arp 116; their designation in Halton Arp's Atlas of Peculiar Galaxies. The galaxy is located on the outskirts of the Virgo Cluster.

Interaction with Messier 60 In optical images, the two galaxies' disks overlap. This has suggested an ongoing interaction, however images do not reveal any signs of star formation which would have been caused by a tidal interaction between the two galaxies. Recent studies of Hubble images made in 2012 of the two galaxies indicate that tidal interactions between the two have just begun.

Interstellar medium of NGC 4647 The gas in NGC 4647 has been mildly disturbed. The galaxy's location in the Virgo Cluster suggests that it might have suffered an effect known as ram-pressure stripping caused by the intracluster medium. Another explanation may be hot gas in the halo of Messier 60. The hot gas in Messier 60 may have increased the pressure of gas on the eastern side of NGC 4647 through either ram-pressure stripping or a bow-shock between the two galaxies causing the observed asymmetry of gas in the galaxy. The difficulty is that the galaxies would have to be so close that tidal forces from Messier 60 would cause the disk of NGC 4647 to get ripped apart.

Supernovae Two supernovae have been observed in NGC 4647:

SN 1979A (type unknown, mag. 15) was discovered by Givi N. Kimeridze on 25 January 1979. SN 2022hrs (Type Ia, mag. 15) was discovered by Kōichi Itagaki on 16 April 2022.

See also List of NGC objects (4001–5000) NGC 4567 and NGC 4568

References

External links

NGC 4647 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 4647

Start with the simplest possible case. Write down what NGC 4647 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 4647 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 4647 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 4647

In research: NGC 4647 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 4647 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 4647 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Arp objects, Astronomical objects discovered in 1784, IRAS catalogue objects, so understanding it makes those chapters shorter.
In everyday life: Look for NGC 4647 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 4647 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what NGC 4647 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 4647 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is NGC 4647 in simple terms?

Why does NGC 4647 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 4647?

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 4647.