astronomy

HD 149382

HD 149382 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 149382 rather than just read about it. In short: HD 149382 is a hot subdwarf star in the constellation of Ophiuchus with an apparent visual magnitude of 8.943. This is too faint to be seen with the naked eye even under ideal conditions, although it can be viewed with a small telescope.

Key takeaways

HD 149382 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 149382 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of HD 149382 from memory before moving on to harder problems.

Reference excerpt

HD 149382 is a hot subdwarf star in the constellation of Ophiuchus with an apparent visual magnitude of 8.943. This is too faint to be seen with the naked eye even under ideal conditions, although it can be viewed with a small telescope. Based upon parallax measurements, this star is located at a distance of about 246 light-years (75.5 parsecs) from the Earth. This is the brightest known B-type subdwarf star with a stellar classification of B5 VI. It is generating energy through the thermonuclear fusion of helium at its core (triple-alpha process). The effective temperature of the star's outer envelope is about 35,500 K, giving it the characteristic blue-white hue of a B-type star. Although only about one seventh the diameter of the Sun, it radiates about 25 times as much due to its high temperature. HD 149382 has a visual companion located at an angular separation of 1 arcsecond. In 2009, a substellar companion, perhaps even a superjovian planet, was announced orbiting the star. This candidate object was estimated to have 8 to 23 times the mass of Jupiter. In 2011, this discovery was thrown into doubt when an independent team of astronomers were unable to confirm the detection. Their observations rule out a companion with a mass greater than Jupiter orbiting with a period of less than 28 days.

Worked examples

Example 1 — a first encounter with HD 149382

Start with the simplest possible case. Write down what HD 149382 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 149382 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 149382 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 149382

In research: HD 149382 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 149382 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 149382 is common in secondary-school and first-year university syllabi. It links to neighbouring topics B-type subdwarfs, Durchmusterung objects, Henry Draper Catalogue objects, so understanding it makes those chapters shorter.
In everyday life: Look for HD 149382 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 149382 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what HD 149382 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 149382 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is HD 149382 in simple terms?

Why does HD 149382 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 149382?

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 149382.