astronomy

HD 82205

HD 82205 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 HD 82205 rather than just read about it. In short: HD 82205 (HR 3770) is a solitary star in the southern constellation Antlia. It is faintly visible to the naked eye with an apparent magnitude of 5.48 and is estimated to be 810 light years distant based on parallax measurements.

Key takeaways

HD 82205 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect HD 82205 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of HD 82205 from memory before moving on to harder problems.

Reference excerpt

HD 82205 (HR 3770) is a solitary star in the southern constellation Antlia. It is faintly visible to the naked eye with an apparent magnitude of 5.48 and is estimated to be 810 light years distant based on parallax measurements. However, it is receding with a heliocentric radial velocity of 12 km/s. HD 82205 has a general stellar classification of K3 III, indicating that it is a red giant. However, Houk and Cowley (1982) found a slightly warmer class of K2 III CNII, which also suggests a strong overabundance of cyano radicals in the stellar atmosphere. At present it has 4.46 times the mass of the Sun but has expanded to 38.9 times its girth. It shines with a luminosity of 552 L☉ from its enlarged photosphere at an effective temperature of 4,413 K, giving an orange hue. HD 82205 has a metallicity 123% that of the Sun and is believed to be a member of the thin disk population. Currently, it spins with a projected rotational velocity lower than 1 km/s. There is a 14th magnitude optical companion separated 12.4 arcseconds away along a position angle of 131°. The object was first noticed by T.J.J See in 1897.

References

External links Image HD 82205

Worked examples

Example 1 — a first encounter with HD 82205

Start with the simplest possible case. Write down what HD 82205 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 HD 82205 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 HD 82205 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 HD 82205

In research: HD 82205 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 HD 82205 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: HD 82205 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Antlia, Bright Star Catalogue objects, Double stars, so understanding it makes those chapters shorter.
In everyday life: Look for HD 82205 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 HD 82205 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what HD 82205 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 HD 82205 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is HD 82205 in simple terms?

Why does HD 82205 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 HD 82205?

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 HD 82205.