astronomy

K2-72d

K2-72d 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 K2-72d rather than just read about it. In short: K2-72d is a small exoplanet orbiting around the red dwarf star K2-72 approximately 227.7 light-years away. K2-72d completes an orbit in 7.8 days, and it has a radius of only 73% of that of the Earth.

Key takeaways

K2-72d belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect K2-72d to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of K2-72d from memory before moving on to harder problems.

Reference excerpt

K2-72d is a small exoplanet orbiting around the red dwarf star K2-72 approximately 227.7 light-years away. K2-72d completes an orbit in 7.8 days, and it has a radius of only 73% of that of the Earth.

Host star

The planet orbits a (M-type) red dwarf star named K2-72, orbited by a total of four planets, of which K2-72e has the longest orbital period. The star has a mass of 0.27 M☉ and a radius of 0.33 R☉. It has a temperature of 3360 K and its age is unknown. In comparison, the Sun is 4.6 billion years old and has a surface temperature of 5778 K. The star's apparent magnitude, or how bright it appears from Earth's perspective, is 15.309. Therefore, it is too dim to be seen with the naked eye and can only be observed with a telescope.

Discovery The planet, along with the other three planets in the K2-72 system, were announced in mid-July 2016 as part of the new results from the second mission of the Kepler spacecraft.

References

Worked examples

Example 1 — a first encounter with K2-72d

Start with the simplest possible case. Write down what K2-72d 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 K2-72d 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 K2-72d 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 K2-72d

In research: K2-72d 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 K2-72d 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: K2-72d is common in secondary-school and first-year university syllabi. It links to neighbouring topics Aquarius (constellation), Exoplanet stubs, Exoplanets discovered by K2, so understanding it makes those chapters shorter.
In everyday life: Look for K2-72d 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 K2-72d in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what K2-72d 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 K2-72d out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is K2-72d in simple terms?

K2-72d is a small exoplanet orbiting around the red dwarf star K2-72 approximately 227.7 light-years away. K2-72d completes an orbit in 7.8 days, and it has a radius of only 73% of that of the Earth.

Why does K2-72d 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 K2-72d?

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 K2-72d.