astronomy

K2-332 b

K2-332 b 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 K2-332 b rather than just read about it. In short: K2-332 b (also EPIC 211579112.01) is a potentially habitable Super-Earth or Mini-Neptune exoplanet with a radius of 2.2 Earths. It is in the empirical habitable zone, receiving 1.17 times the light that Earth gets from the sun.

Key takeaways

K2-332 b belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect K2-332 b to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of K2-332 b from memory before moving on to harder problems.

Reference excerpt

K2-332 b (also EPIC 211579112.01) is a potentially habitable Super-Earth or Mini-Neptune exoplanet with a radius of 2.2 Earths. It is in the empirical habitable zone, receiving 1.17 times the light that Earth gets from the sun. Its star, K2-332, is type M4V, with a temperature of ~3300 K. It was detected using the transit method in 2016 and is 402 light-years away.

Discovery The planet is confirmed to exist and was discovered by the K2 "Second Light" mission in 2016. It was originally referred to by its EPIC designation. The average transit time is 2 hours and 2 minutes and the average depth is 0.6508%. The object's star is within the 2MASS catalog.

Characteristics

Mass, radius, and temperature The planet has an estimated mass of 5.47 earths, and at a radius of more than twice that of the Earth, the density corresponds to that of a watery or gaseous Mini-Neptune rather than a rocky Super-Earth. It has an equilibrium temperature of 266 K (−7 °C; 19 °F), somewhat higher than Earth's.

Orbit and host star The planet orbits within the inner part of the habitable zone, about 1/3 of the way between the runaway G limit for Super-Earths and the absolute inner edge. Its orbital period is 17.7 days, but the planet has an unknown semi-major axis. Its star is a dim red dwarf with about 20% the mass and size of the sun. In its habitable-zone orbit, the planet receives 1.17 times the insolation Earth gets from the sun.

Habitability

General habitability and atmosphere The planet is large (over 2 Earth-radii) and has a low density consistent with that of a watery or Neptune-like planet and not a silicate planet or a partially metallic planet like Earth. This compromises its habitability, for a solid surface is required for life to develop spontaneously on a planet. However, 2021 studies show that sub-Neptunes have an abundance of water and life-friendly molecules (nitrogen, oxygen, CO2, etc.) in their atmospheres, and the area with habitable temperatures and pressures is fairly stable. As a result, K2-332 b could be a habitable planet despite its extremely low density. If the system has a leftover dust disk or asteroid/comet belt, panspermia of microbial life from a terrestrial planet or earthlike moon could occur, and the organisms would have enough time to reproduce before dying due to the harsh conditions. 2019 studies of the TOI-270 system support the notion that Mini-Neptunes have life-friendly atmospheres rich in organic matter.

Tidal locking The planet is very close to its star with a low eccentricity, so it is likely to be tidally locked, with one side always facing the star. In this case, the dayside would be extremely hot, while the nightside would be cold enough to freeze an atmosphere on a terrestrial planet, where the terminator line and adjacent twilight region would be the only habitable parts of the planet. This occurs in 4.5 Gyrs in planets orbiting stars M1 and later, and in 1 Gyr in planets around stars M7 and later. However, oceanic currents and wind can distribute heat evenly around a planet (any planet, not just an Earth-size one), warming the nightside past the freezing point of the atmosphere and cooling the dayside to below 100 °C. The area in the life-friendly pressure tier of the atmosphere that would also have habitable temperatures would then extend to 55° in both hemispheres on the dayside and around the nightside near the equator, with a maximum temperature of ~42 °F (6 °C). For higher levels of carbon dioxide, this area could even extend around the entire planet (minus the nadir and high polar regions).

Worked examples

Example 1 — a first encounter with K2-332 b

Start with the simplest possible case. Write down what K2-332 b 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 K2-332 b 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 K2-332 b 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 K2-332 b

In research: K2-332 b 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 K2-332 b 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: K2-332 b is common in secondary-school and first-year university syllabi. It links to neighbouring topics Exoplanets discovered in 2016, K2, Super-Earths, so understanding it makes those chapters shorter.
In everyday life: Look for K2-332 b 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 K2-332 b in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what K2-332 b 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 K2-332 b out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is K2-332 b in simple terms?

Why does K2-332 b 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 K2-332 b?

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 K2-332 b.