astronomy

Kepler-46

Kepler-46 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 Kepler-46 rather than just read about it. In short: Kepler-46, previously designated KOI-872, is a star located in the constellation Lyra. Observed since 2009 by the Kepler space observatory, it has since been found to possess a planetary system consisting of at least three planets and while it has a similar mass to the Sun (90%) it is significantly older at ten billion years.

Key takeaways

Kepler-46 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Kepler-46 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Kepler-46 from memory before moving on to harder problems.

Reference excerpt

Kepler-46, previously designated KOI-872, is a star located in the constellation Lyra. Observed since 2009 by the Kepler space observatory, it has since been found to possess a planetary system consisting of at least three planets and while it has a similar mass to the Sun (90%) it is significantly older at ten billion years. Kepler-46 b (previously KOI-872.01), was the first planet discovered in the system. It was found through detailed analysis of Kepler space observatory data. An additional planet, Kepler-46 c, was discovered by an outside group using Kepler public data through analysis of transit timing variations. While only one additional planet was confirmed by the analysis, the study revealed the potential existence of an unconfirmed planet KOI-872.03 (KOI-872 d). Validation by the multiplicity method confirmed the existence of this planet which was then renamed Kepler-46d.

Planetary system Planet b is a gas giant planet with a mass slightly less than that of Jupiter. The second planet in the system was among the first to be discovered through the method of transit timing variations, and through its confirmation of KOI-872 c with a 99% confidence level has shown that the method of detection may be used to detect future extrasolar planets and, possibly, extrasolar moons. This second planet exerted a gravitational force on the first planet, orbiting its host star in just 34 days. While this usually occurs on an extremely regular schedule, additional planets within the system can disrupt the time of the transit, and these disruptions can indicate the presence of a planet, even if the disrupting planet does not pass in front of the host star itself. The data show that Kepler-46 c is an approximately Saturn-mass object with an orbital period of 57 days. As the planet does not itself transit its host star, there is no way of knowing its size (probably a similar size to its sibling). The measurements also suggest the existence of another planet orbiting with a period of about 6.8 days, and this planet was confirmed in 2016. The method in which the planet was detected is similar to the way that the planet Neptune was discovered, in which the newly discovered planet is detected by its pull on another which is already known to exist. In 2021, it was found the orbital plane of Kepler-46b is slowly changing, likely under the gravitational influence of the additional giant planet.

References

Worked examples

Example 1 — a first encounter with Kepler-46

Start with the simplest possible case. Write down what Kepler-46 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 Kepler-46 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 Kepler-46 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 Kepler-46

In research: Kepler-46 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 Kepler-46 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: Kepler-46 is common in secondary-school and first-year university syllabi. It links to neighbouring topics G-type main-sequence stars, Kepler objects of interest, Lyra, so understanding it makes those chapters shorter.
In everyday life: Look for Kepler-46 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 Kepler-46 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Kepler-46 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 Kepler-46 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Kepler-46 in simple terms?

Why does Kepler-46 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 Kepler-46?

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 Kepler-46.