astronomy

K2-229

K2-229 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 K2-229 rather than just read about it. In short: K2-229 (also designated EPIC 228801451 or TYC 4947-834-1) is a K-type main sequence star approximately 103 parsecs (335 light years) away in the constellation Virgo. It was observed by the Kepler Space Telescope during its K2 "Second Light" mission in Campaign 10.

Key takeaways

K2-229 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect K2-229 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of K2-229 from memory before moving on to harder problems.

Reference excerpt

K2-229 (also designated EPIC 228801451 or TYC 4947-834-1) is a K-type main sequence star approximately 103 parsecs (335 light years) away in the constellation Virgo. It was observed by the Kepler Space Telescope during its K2 "Second Light" mission in Campaign 10.

Planetary system As of March 27, 2018, K2-229 has a system of three confirmed exoplanets.

All three known planets transit their star and would orbit inside that of Mercury if placed in the Solar System. Only the innermost has a well determined mass and composition.

K2-229b

K2-229b is a Super-Earth with an iron-rich composition. It is about 17% larger than Earth by radius, but is almost 2.6 times more massive. Its high density indicates it has a core-mass fraction of about 68%, nearly identical to that of Mercury. It is believed that like Mercury, the huge core of K2-229 is the result of a giant impact event. However, unlike Mercury, it orbits extremely close to its host star, with one orbit taking a little over 14 hours to complete. K2-229b has a temperature of over 1,960 K to 2,330 K, hot enough to melt iron and likely giving it an atmosphere of silicate vapor.

K2-229c K2-229c is a Mini-Neptune sized planet with a radius of 2.12 R🜨. Its mass has not been accurately determined, so only an upper limit of 21.3 M🜨 can be given. However, a different method of radial velocity analysis gives the planet's mass at about 9.5 M🜨. With an orbital period of 8.32 days, K2-229c has an equilibrium temperature of 800 K (527 °C; 980 °F) and a dayside temperature of 962 K (689 °C; 1,272 °F).

K2-229d K2-229d is another Mini-Neptune with a radius of 2.64 R🜨, meaning it is likely gaseous. Only a maximum mass of 25.1 M🜨 could be determined. The planet was detected by a single transit event lasting about two and a half hours long. There were two models for its orbital period: one where it took about 31 days to orbit and the second transit was during a large data gap; and another where it took over 50 days to orbit. The latter scenario was considered unlikely, as K2-229d would need to have a very eccentric orbit to exhibit such a short transit duration – so eccentric that its periapsis would cross the orbit of K2-229c and destabilize the system. It has an equilibrium temperature of 522 K (249 °C; 480 °F).

Worked examples

Example 1 — a first encounter with K2-229

Start with the simplest possible case. Write down what K2-229 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 K2-229 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 K2-229 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 K2-229

In research: K2-229 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 K2-229 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: K2-229 is common in secondary-school and first-year university syllabi. It links to neighbouring topics K-type main-sequence stars, Planetary systems with three confirmed planets, Planetary transit variables, so understanding it makes those chapters shorter.
In everyday life: Look for K2-229 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 K2-229 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what K2-229 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 K2-229 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is K2-229 in simple terms?

Why does K2-229 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 K2-229?

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 K2-229.