astronomy

Kepler-4b

Kepler-4b 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-4b rather than just read about it. In short: Kepler-4b, initially known as KOI 7.01, is an extrasolar planet first detected as a transit by the Kepler spacecraft. Its radius and mass are similar to that of Neptune; however, due to its proximity to its host star, it is substantially hotter than any planet in the Solar System.

Key takeaways

Kepler-4b 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-4b to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Kepler-4b from memory before moving on to harder problems.

Reference excerpt

Kepler-4b, initially known as KOI 7.01, is an extrasolar planet first detected as a transit by the Kepler spacecraft. Its radius and mass are similar to that of Neptune; however, due to its proximity to its host star, it is substantially hotter than any planet in the Solar System. The planet's discovery was announced on January 4, 2010, in Washington, D.C., along with four other planets that were initially detected by the Kepler spacecraft and subsequently confirmed by telescopes at the W.M. Keck Observatory.

Nomenclature and history Kepler-4b was named because it was the first planet discovered in the orbit of its star, Kepler-4. The star was, in turn, named for the Kepler Mission, a NASA satellite whose purpose is to discover Earth-like planets in a section of the sky between constellations Cygnus and Lyra using the transit method. Using this method, Kepler notes small and steady decreases in a star's brightness that are measured as a planet crosses in front of it. Initially, Kepler-4b was detected as a transit event by the Kepler telescope and considered a Kepler Object of Interest with the designation KOI 7.01. Subsequent radial velocity measurements by the High Resolution Echelle Spectrometer on the telescopes of W.M. Keck Observatory confirmed the planetary nature of the transit event and established a mass estimate for the planet. The planet's discovery was announced on January 4, 2010, along with four other planets detected by Kepler: Kepler-5b, 6b, 7b and 8b at the 215th meeting of the American Astronomical Society in Washington, D.C.

Host star

Kepler-4 is a star very similar to the sun located about 1610 light-years away from Earth, in the constellation of Draco.

Characteristics Kepler-4b orbits its host star in 3.213 days at a distance of 0.046 AU. This places it almost 10 times closer to its star than Mercury is to the Sun. Consequently, Kepler-4b is thought to be extremely hot, with an equilibrium temperature greater than 1700 kelvins (2600 °F). (1426°C) The planet is estimated to be 25 times more massive than the Earth with a radius that is 4 times greater than the Earth. This makes it similar to Neptune in terms of size and mass, but with a temperature that is not comparable to any planet in the Solar System (Venus, the hottest planet, is only 735 kelvins). Kepler-4b's eccentricity was assumed to be 0, however an independent reanalysis of the discovery data found a value of 0.25 ± 0.12, and a later reanalysis of the light curve discovered a secondary eclipse with depth 7.47 ± 1.82ppm at a phase of about 0.7.

See also List of exoplanets discovered by the Kepler space telescope

References

External links Media related to Kepler-4 b at Wikimedia Commons

NASA.gov

Illustrations

Worked examples

Example 1 — a first encounter with Kepler-4b

Start with the simplest possible case. Write down what Kepler-4b 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-4b 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-4b 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-4b

In research: Kepler-4b 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-4b 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-4b is common in secondary-school and first-year university syllabi. It links to neighbouring topics Draco (constellation), Exoplanets discovered by the Kepler space telescope, Exoplanets discovered in 2010, so understanding it makes those chapters shorter.
In everyday life: Look for Kepler-4b 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-4b in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Kepler-4b 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-4b out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Kepler-4b in simple terms?

Why does Kepler-4b 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-4b?

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-4b.