astronomy

V718 Coronae Australis

V718 Coronae Australis 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 V718 Coronae Australis rather than just read about it. In short: V718 Coronae Australis (HD 171697; HR 6991; V718 CrA) is a solitary variable star located in the southern constellation Corona Australis. It is faintly visible to the naked eye as a red-hued point of light with an apparent magnitude of 5.43.

Key takeaways

V718 Coronae Australis belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect V718 Coronae Australis to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of V718 Coronae Australis from memory before moving on to harder problems.

Reference excerpt

V718 Coronae Australis (HD 171697; HR 6991; V718 CrA) is a solitary variable star located in the southern constellation Corona Australis. It is faintly visible to the naked eye as a red-hued point of light with an apparent magnitude of 5.43. Gaia DR3 parallax measurements imply a distance of 630 light years and it is currently receding with a heliocentric radial velocity of 28.5 km/s. At its current distance V718 CrA's brightness is diminished by 0.37 magnitudes due to interstellar dust and it has an absolute magnitude of −1.03.

This object was first noticed to be potentially variable by Olin J. Eggen in 1973. Its variability was confirmed in 1999 after subsequent observations and was given the variable star designation V718 Coronae Australis. Observations from Koen & Laney (2000) reveal that V718 CrA has two periods: one lasting 5.37 days and the other lasting 71.1 days. It is a slow irregular variable of subtype Lb that fluctuates between 5.45 and 5.51 in the Hipparcos passband. V718 CrA has a stellar classification of M2 III, indicating that it is an evolved red giant. It is currently on the asymptotic giant branch, fusing hydrogen and helium shells around an inert carbon core. It has 1.45 times the mass of the Sun but it has expanded to 101 times the Sun's radius. It radiates 1,001 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 3,698 K. Oscillation measurements from Koen & Laney (2000) yield a mass of 2 M☉.

References

Illustrations

Worked examples

Example 1 — a first encounter with V718 Coronae Australis

Start with the simplest possible case. Write down what V718 Coronae Australis 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 V718 Coronae Australis 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 V718 Coronae Australis 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 V718 Coronae Australis

In research: V718 Coronae Australis 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 V718 Coronae Australis 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: V718 Coronae Australis is common in secondary-school and first-year university syllabi. It links to neighbouring topics Asymptotic-giant-branch stars, Bright Star Catalogue objects, Corona Australis, so understanding it makes those chapters shorter.
In everyday life: Look for V718 Coronae Australis 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 V718 Coronae Australis in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what V718 Coronae Australis 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 V718 Coronae Australis out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is V718 Coronae Australis in simple terms?

Why does V718 Coronae Australis 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 V718 Coronae Australis?

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 V718 Coronae Australis.