science

NGC 663

NGC 663 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 663 rather than just read about it. In short: NGC 663 (also known as Caldwell 10) is a young open cluster located 8,800 light years from Earth in the constellation of Cassiopeia. It has an estimated 400 stars and spans about a quarter of a degree across the sky.

Key takeaways

NGC 663 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 663 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of NGC 663 from memory before moving on to harder problems.

Reference excerpt

NGC 663 (also known as Caldwell 10) is a young open cluster located 8,800 light years from Earth in the constellation of Cassiopeia. It has an estimated 400 stars and spans about a quarter of a degree across the sky. It can reportedly be detected with the unaided eye, although a telescope is recommended for best viewing. The brightest members of the cluster can be viewed with binoculars. Although the listed visual magnitude is 7.1, several observers have reported higher estimates. Based on its parallax as measured by Gaia, it is located about 2,700 parsecs distant with an estimated age of 20–25 million years. This means that stars of spectral class B2 or higher (in the sense of higher mass), are reaching the end of their main sequence lifespan. This cluster appears to be located in front of a molecular cloud, although the two are not physically associated. This cloud has the effect of blocking background stars from the visual image of the cluster as it lies at a distance of 300 parsecs. This cluster is of interest because of the high number of Be stars, with a total of about 24 discovered. These are spectral class B stars that show prominent emission lines of hydrogen in their spectrum. Most of the Be stars in the cluster lie between spectral class B0 and B3. A candidate member of the cluster, LS I +61° 235, is a Be star with an X-ray binary component that has a period of about three years. There are at least five blue stragglers in the cluster. These are stars that formed by the merger of two other stars. Two of the cluster's star systems are likely eclipsing binaries with periods of 0.6 and 1.03 days. NGC 663 also has two red supergiant stars, both located on its periphery The star cluster is assumed to form part of the stellar association Cassiopeia OB8, that is located in the Perseus Arm of the Milky Way, along with the open clusters M103, NGC 654, NGC 659, and some supergiant stars scattered between them, all of them having similar ages and distances. It is likely the most massive star cluster in the Cassiopeia OB8 association, and possibly the Perseus Arm.

References

External links

NGC 663 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 663

Start with the simplest possible case. Write down what NGC 663 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 663 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 663 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 663

In research: NGC 663 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 663 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 663 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Caldwell objects, Cassiopeia (constellation), NGC objects, so understanding it makes those chapters shorter.
In everyday life: Look for NGC 663 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 663 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what NGC 663 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 663 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is NGC 663 in simple terms?

Why does NGC 663 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 663?

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 663.