astronomy

Gliese 408

Gliese 408 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 408 rather than just read about it. In short: Gliese 408 is a star located 22.0 light-years (6.7 parsecs) from the Solar System, located in the constellation of Leo. The stars nearest to Gliese 408 are Gliese 402, at 6.26 light years, and AD Leonis, at 6.54 light years.

Key takeaways

Gliese 408 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 408 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Gliese 408 from memory before moving on to harder problems.

Reference excerpt

Gliese 408 is a star located 22.0 light-years (6.7 parsecs) from the Solar System, located in the constellation of Leo. The stars nearest to Gliese 408 are Gliese 402, at 6.26 light years, and AD Leonis, at 6.54 light years. Gliese 408 is a red dwarf with a spectral type of M2.5V. Much dimmer than the Sun, it has a luminosity of only 0.37% compared to the Sun, but still it is much more luminous than other red dwarf stars, like Proxima Centauri. Its effective temperature is about 3400 to 3500 K; its mass is about 41% compared to the Sun, and its radius is about 43% that of the Sun. Its rotational velocity is at most 2.3 km/s. No evidence of a circumstellar disk has been found around Gliese 408.

References

Worked examples

Example 1 — a first encounter with Gliese 408

Start with the simplest possible case. Write down what Gliese 408 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 408 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 408 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 408

In research: Gliese 408 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 408 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 408 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Gliese and GJ objects, Hipparcos objects, Leo (constellation), so understanding it makes those chapters shorter.
In everyday life: Look for Gliese 408 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 408 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Gliese 408 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 408 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Gliese 408 in simple terms?

Why does Gliese 408 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 408?

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 408.