astronomy

V723 Monocerotis

V723 Monocerotis 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 V723 Monocerotis rather than just read about it. In short: V723 Monocerotis is a binary star in the constellation Monoceros. It is an ellipsoidal variable about 1,500 light-years distant, too faint to be seen to the naked eye, with a variable apparent magnitude between 8.21 and 8.42.

Key takeaways

V723 Monocerotis belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect V723 Monocerotis to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of V723 Monocerotis from memory before moving on to harder problems.

Reference excerpt

V723 Monocerotis is a binary star in the constellation Monoceros. It is an ellipsoidal variable about 1,500 light-years distant, too faint to be seen to the naked eye, with a variable apparent magnitude between 8.21 and 8.42. It was proposed in 2021 to be a binary system including a lower mass gap black hole candidate nicknamed "The Unicorn". Located 1,500 light years from Earth, it would be the closest known black hole, and among the smallest ever found with a mass 3 times the mass of the Sun, corresponding to a Schwarzschild radius of 9 kilometers. Follow-up work in 2022 argued that V723 Monocerotis does not contain a black hole, but is a mass-transfer binary containing a red giant that has been stripped of much of its mass, and a subgiant star. The primary red giant star has 25 times the Sun's radius but an unusually low mass of 0.44 solar masses due to mass transfer to its partner. The secondary star is 2.8 times more massive than the Sun and 8.3 times larger, a subgiant approaching the base of the red giant branch. The primary is more than a 100 times as luminous as the Sun, while the secondary is about 70 times as luminous.

References

Further reading Masuda, Kento; Hirano, Teruyuki (April 2021). "Tidal Effects on the Radial Velocities of V723 Mon: Additional Evidence for a Dark 3 M⊙ Companion". The Astrophysical Journal Letters. 910 (2): 10. arXiv:2103.05216. Bibcode:2021ApJ...910L..17M. doi:10.3847/2041-8213/abecdc. S2CID 232168389. L17.

Illustrations

Worked examples

Example 1 — a first encounter with V723 Monocerotis

Start with the simplest possible case. Write down what V723 Monocerotis 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 V723 Monocerotis 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 V723 Monocerotis 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 V723 Monocerotis

In research: V723 Monocerotis 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 V723 Monocerotis 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: V723 Monocerotis is common in secondary-school and first-year university syllabi. It links to neighbouring topics Binary stars, G-type bright giants, Henry Draper Catalogue objects, so understanding it makes those chapters shorter.
In everyday life: Look for V723 Monocerotis 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 V723 Monocerotis in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what V723 Monocerotis 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 V723 Monocerotis out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is V723 Monocerotis in simple terms?

Why does V723 Monocerotis 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 V723 Monocerotis?

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 V723 Monocerotis.