astronomy

TOI-157

TOI-157 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 TOI-157 rather than just read about it. In short: TOI-157 (also known as TIC 140691463) is a G-type subgiant star located about 1160 light years (356 pc) from Earth. It has a mass of about 0.92 solar masses, a radius of about 1.1 solar radii and a temperature of about 5600 K.

Key takeaways

TOI-157 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect TOI-157 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of TOI-157 from memory before moving on to harder problems.

Reference excerpt

TOI-157 (also known as TIC 140691463) is a G-type subgiant star located about 1160 light years (356 pc) from Earth. It has a mass of about 0.92 solar masses, a radius of about 1.1 solar radii and a temperature of about 5600 K. It is approximately 12.0 to 12.8 billion years old.

Planetary system It has one discovered exoplanet orbiting it named TOI-157b. It is a gas giant classed as a hot Jupiter with a mass of 1.18 Jupiter masses and a radius of 1.286 Jupiter radii. It orbits very close to the star taking only 2 days to complete an orbit. This places the temperature of TOI-157b to be around 1588 Kelvin. Using TESS data discrepant transit parameters as well as empirical limb-darkening coefficients could be determined. Further analysis revealed that the radius ratio of planet to star is 7.8 ± 0.4 % higher than previously determined, caused by blending with the light from background stars, at a new value of 0.1229 ± 0.0005.

Age It is a typical hot Jupiter. However, at an age of 12.82+0.73−1.4 billion years the planet is currently the oldest discovered and only about 1 billion years younger than the age of the universe at about 13.8 billion years and part of the list of exoplanet extremes. Only PSR B1620-26 b with 11.2–12.7 Gyr remains as alternatively oldest exoplanet.

References

Illustrations

Worked examples

Example 1 — a first encounter with TOI-157

Start with the simplest possible case. Write down what TOI-157 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 TOI-157 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 TOI-157 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 TOI-157

In research: TOI-157 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 TOI-157 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: TOI-157 is common in secondary-school and first-year university syllabi. It links to neighbouring topics G-type subgiants, Mensa (constellation), Planetary systems with one confirmed planet, so understanding it makes those chapters shorter.
In everyday life: Look for TOI-157 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 TOI-157 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what TOI-157 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 TOI-157 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is TOI-157 in simple terms?

Why does TOI-157 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 TOI-157?

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 TOI-157.