science

NGC 6388

NGC 6388 is a science 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 6388 rather than just read about it. In short: NGC 6388 is a globular cluster of stars located in the southern constellation of Scorpius. The cluster was discovered by Scottish astronomer James Dunlop on May 13, 1826 using a 20 cm (9 in) reflector telescope.

Key takeaways

NGC 6388 belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect NGC 6388 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of NGC 6388 from memory before moving on to harder problems.

Reference excerpt

NGC 6388 is a globular cluster of stars located in the southern constellation of Scorpius. The cluster was discovered by Scottish astronomer James Dunlop on May 13, 1826 using a 20 cm (9 in) reflector telescope. It was later determined to be a globular cluster by English astronomer John Herschel, who was able to resolve it into individual stars. NGC 6388 is located at a distance of approximately 35,600 light-years (10.90 kpc) from the Sun. Due to its apparent visual magnitude of +6.8, binoculars or a small telescope are required to view it. This cluster has an age of 11.5±1.5 Gyr and a core radius of 7.2″. The central velocity dispersion is 18.9 km/s, and the central density is 2.19×105 L☉·pc−3. With an estimated mass of 2.17×106 M☉, it is one of the most massive globular clusters in the Milky Way. Multiple stellar populations have been detected. In the past it has been proposed that this cluster was accreted into the Milky Way galaxy. However, the abundance of stellar elements from a large sample of cluster members strongly indicate it was formed within the galaxy. The Hertzsprung–Russell diagram for NGC 6388 shows that the main-sequence turnoff for this cluster is similar to that of the cluster 47 Tucanae. This suggests that the bulk of the stellar components have a similar age and chemical abundances between the two clusters. However, the RR Lyrae variables and hotter members of the horizontal branch in NGC 6388 appear overluminous. It has been suggested that this extended horizontal branch may be the result of a central intermediate mass black hole (IMBH). X-ray observations of the cluster rule out an accreting IMBH, but not a quiescent black hole. The stellar density and radial profiles of velocity dispersion rule out an IMBH with a mass greater than about 2,000 M☉. The cluster contains a population of blue straggler stars (BSS), which are the result of stellar mergers. The radial distribution of this population is high near the core, decreasing at intermediate distance before increasing again at larger radii. This bimodal distribution is similar to that in other globulars. However, the scale of the population at intermediate distances suggests that dynamic friction in NGC 6388 is less efficient at segregating BSS toward the core. Examination of NGC 6388 by the Chandra observatory show 61 X-ray sources within a half-mass radius of the core (0.67′), with all having luminosities above 5×1030 erg. Five of these appear to be X-ray binaries.

References

Illustrations

Worked examples

Example 1 — a first encounter with NGC 6388

Start with the simplest possible case. Write down what NGC 6388 claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, 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 6388 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 6388 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 6388

In research: NGC 6388 appears in science 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 6388 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 6388 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Globular clusters, NGC objects, Scorpius, so understanding it makes those chapters shorter.
In everyday life: Look for NGC 6388 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 6388 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what NGC 6388 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 6388 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is NGC 6388 in simple terms?

Why does NGC 6388 matter?

Because it connects several science 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 6388?

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 6388.