astronomy

HD 10390

HD 10390 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 10390 rather than just read about it. In short: HD 10390 (HR 490; 6 H. Trinaguli) is a solitary star located in the northern constellation Triangulum.

Key takeaways

HD 10390 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 10390 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of HD 10390 from memory before moving on to harder problems.

Reference excerpt

HD 10390 (HR 490; 6 H. Trinaguli) is a solitary star located in the northern constellation Triangulum. It is faintly visible to the naked eye as a bluish-white hued point of light with an apparent magnitude of 5.64. The object is located relatively close at a distance of 292 light-years based on Gaia DR3 parallax measurements and it is drifting closer with a heliocentric radial velocity of −1.9 km/s. At its current distance, HD 10390's brightness is diminished by an interstellar extinction of only five-hundredths of a magnitude and it has an absolute magnitude of +1.00. HD 10390 has a stellar classification of B9 IV-V, indicating that it is a slightly evolved B-type star with a luminosity class intermediate between a subgiant and a main sequence star. Osawa (1959) gave a class of B9 V, instead indicating that it is an ordinary B-type main-sequence star that is generating energy via hydrogen fusion at its core. It has 2.62 times the mass of the Sun and 2.14 times the radius of the Sun. It radiates 51.5 times the luminosity of the Sun from its photosphere at an effective temperature of 11,076 K. HD 10390 is metal defecient with an iron abundance of [Fe/H] = −0.2 or 63.1% of the Sun's and it spins modestly with a projected rotational velocity of 45 km/s, well below its breakup velocity of 355 km/s. Despite the first classification, HD 10390 has only completed 16.8% of its main sequence lifetime at the age of approximately 50 million years.

References

Illustrations

Worked examples

Example 1 — a first encounter with HD 10390

Start with the simplest possible case. Write down what HD 10390 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 10390 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 10390 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 10390

In research: HD 10390 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 10390 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 10390 is common in secondary-school and first-year university syllabi. It links to neighbouring topics B-type main-sequence stars, Bright Star Catalogue objects, Durchmusterung objects, so understanding it makes those chapters shorter.
In everyday life: Look for HD 10390 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 10390 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what HD 10390 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 10390 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is HD 10390 in simple terms?

HD 10390 (HR 490; 6 H. Trinaguli) is a solitary star located in the northern constellation Triangulum.

Why does HD 10390 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 10390?

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 10390.