astronomy

Kepler-289

Kepler-289 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-289 rather than just read about it. In short: Kepler-289 (PH3) is a rotating variable star slightly more massive than the Sun, with a spectral type of G2, 2370 light-years away from Earth in the constellation of Cygnus. It hosts a system of multiple exoplanets.

Key takeaways

Kepler-289 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-289 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Kepler-289 from memory before moving on to harder problems.

Reference excerpt

Kepler-289 (PH3) is a rotating variable star slightly more massive than the Sun, with a spectral type of G2, 2370 light-years away from Earth in the constellation of Cygnus. It hosts a system of multiple exoplanets.

Planetary system Kepler-289 hosts three transiting planets, discovered using the Kepler space telescope. Two planets, Kepler-289b and Kepler-289c, were confirmed in 2014 as part of a study using statistical validation to confirm hundreds of Kepler candidates. A third planet, Kepler-289d, was found by the Planet Hunters citizen science project, hence the other designation for the system, PH3. Different sources present conflicting models of Kepler-289's planetary system. The discovery paper for planet d says that it has an orbital period of 66 days, and that a 330-day candidate is an alias of the true period of planet d. A 2023 follow-up study also reports a 66-day period for planet d. However, a 2025 study reports a 330-day planet, and says that the 66-day signal "is no longer believed to exist in the data". The NASA Exoplanet Archive lists both a 66-day and a 330-day planet, the latter called Kepler-289e, but no literature source claims the existence of more than three planets in the system.

References

Worked examples

Example 1 — a first encounter with Kepler-289

Start with the simplest possible case. Write down what Kepler-289 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-289 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-289 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-289

In research: Kepler-289 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-289 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-289 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Cygnus (constellation), G-type main-sequence stars, Kepler objects of interest, so understanding it makes those chapters shorter.
In everyday life: Look for Kepler-289 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-289 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Kepler-289 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-289 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Kepler-289 in simple terms?

Why does Kepler-289 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-289?

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-289.