astronomy

LP 791-18

LP 791-18 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 LP 791-18 rather than just read about it. In short: LP 791-18 (TOI-736) is a cool red dwarf star in the constellation Crater, located 26.65 parsecs (86.9 light-years) away from Earth. The star is one of the smallest known stars to host exoplanets.

Key takeaways

LP 791-18 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect LP 791-18 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of LP 791-18 from memory before moving on to harder problems.

Reference excerpt

LP 791-18 (TOI-736) is a cool red dwarf star in the constellation Crater, located 26.65 parsecs (86.9 light-years) away from Earth. The star is one of the smallest known stars to host exoplanets. In 2019 two exoplanets in transit around it were announced by TESS, and a third planet was discovered in Spitzer Space Telescope data in 2023.

Planetary system

The innermost planet, b, is a super-Earth and the outermost planet, c, is a sub-Neptune. They were discovered together in 2019. The middle planet, d, is an Earth-mass world discovered in 2023. It may potentially be tidally heated by interactions with planet c, which would lead to abundant volcanoes similar to Jupiter's moon Io. As the planet d is in the inner edge of the habitable zone, liquid water could condense on the side of the planet that faces away from the host star. In 2021 planet c was suggested for atmospheric analysis by the James Webb Space Telescope (JWST). In 2025, by using JWST the atmosphere of planet c was found to be rich in haze and methane (CH4) but without clear evidence for carbon dioxide (CO2), which is unlike that of other temperate sub-Neptune planets including K2-18b and TOI-270d.

Notes

References

Worked examples

Example 1 — a first encounter with LP 791-18

Start with the simplest possible case. Write down what LP 791-18 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 LP 791-18 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 LP 791-18 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 LP 791-18

In research: LP 791-18 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 LP 791-18 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: LP 791-18 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Crater (constellation), M-type main-sequence stars, Planetary systems with three confirmed planets, so understanding it makes those chapters shorter.
In everyday life: Look for LP 791-18 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 LP 791-18 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what LP 791-18 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 LP 791-18 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is LP 791-18 in simple terms?

LP 791-18 (TOI-736) is a cool red dwarf star in the constellation Crater, located 26.65 parsecs (86.9 light-years) away from Earth. The star is one of the smallest known stars to host exoplanets.

Why does LP 791-18 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 LP 791-18?

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 LP 791-18.