astronomy

Gliese 208

Gliese 208 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 Gliese 208 rather than just read about it. In short: Gliese 208 (Gj 208) is a red dwarf star with an apparent magnitude of 8.9. It is 37 light years away in the constellation of Orion.

Key takeaways

Gliese 208 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Gliese 208 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Gliese 208 from memory before moving on to harder problems.

Reference excerpt

Gliese 208 (Gj 208) is a red dwarf star with an apparent magnitude of 8.9. It is 37 light years away in the constellation of Orion. It is an extremely wide binary with 2MASS J0536+1117, an M4 star 2.6 arcminutes away (at least 0.028 light years) The spectral type of Gj 208 has variously been described between K6 and M1. Two of the most recent observations give a statistically calculated spectral type of K7.9 or a more traditional classification of M0.0 Ve. It is a cool dwarf star and probably a spectroscopic binary. Calculations from 2010 suggest that this star passed as close as 1.537 parsecs (5.0 light-years) from the Sun about 500,000 years ago. GJ 208 is an RS Canum Venaticorum variable, close binary systems which show small amplitude brightness changes caused by chromospheric activity. Its visual magnitude varies by about a quarter magnitude with a period of 12.285 days.

References

External links Wikisky image Archived 2012-10-11 at the Wayback Machine of HD 245409 (Gliese 208)

Illustrations

Worked examples

Example 1 — a first encounter with Gliese 208

Start with the simplest possible case. Write down what Gliese 208 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 Gliese 208 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 Gliese 208 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 Gliese 208

In research: Gliese 208 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 Gliese 208 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: Gliese 208 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Durchmusterung objects, Emission-line stars, Gliese and GJ objects, so understanding it makes those chapters shorter.
In everyday life: Look for Gliese 208 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 Gliese 208 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Gliese 208 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 Gliese 208 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Gliese 208 in simple terms?

Gliese 208 (Gj 208) is a red dwarf star with an apparent magnitude of 8.9. It is 37 light years away in the constellation of Orion.

Why does Gliese 208 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 Gliese 208?

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 Gliese 208.