astronomy

HD 102839

HD 102839 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 102839 rather than just read about it. In short: HD 102839 is a yellow hued supergiant star in the southern constellation of Musca. With an apparent visual magnitude of 4.98, it is faintly visible to the naked eye under good viewing conditions.

Key takeaways

HD 102839 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 102839 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of HD 102839 from memory before moving on to harder problems.

Reference excerpt

HD 102839 is a yellow hued supergiant star in the southern constellation of Musca. With an apparent visual magnitude of 4.98, it is faintly visible to the naked eye under good viewing conditions. Based on a parallax of 2.11 mas, it is located at a distance of approximately 1,550 light-years (480 pc) away from Earth. The star is drifting further away with a line of sight velocity component of +16 km/s. This star has a stellar classification of G6Ib, matching an evolved G-type supergiant star. With 2.3 times the mass of the Sun, it has expanded to 78 times the Sun's radius. It is spinning with a projected rotational velocity of 7.6 km/s. HD 102839 is radiating almost 1,600 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 4,500 K.

References

Illustrations

Worked examples

Example 1 — a first encounter with HD 102839

Start with the simplest possible case. Write down what HD 102839 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 102839 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 102839 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 102839

In research: HD 102839 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 102839 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 102839 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Bright Star Catalogue objects, Durchmusterung objects, G-type supergiants, so understanding it makes those chapters shorter.
In everyday life: Look for HD 102839 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 102839 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what HD 102839 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 102839 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is HD 102839 in simple terms?

HD 102839 is a yellow hued supergiant star in the southern constellation of Musca. With an apparent visual magnitude of 4.98, it is faintly visible to the naked eye under good viewing conditions.

Why does HD 102839 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 102839?

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 102839.