astronomy

K2-141b

K2-141b 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 K2-141b rather than just read about it. In short: K2-141b (also designated EPIC 246393474.01) is a massive rocky exoplanet orbiting extremely close to a K Type orange main-sequence star K2-141. The planet was first discovered by the Kepler space telescope during its K2 “Second Light” mission and later observed by the HARPS-N spectrograph.

Key takeaways

K2-141b belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect K2-141b to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of K2-141b from memory before moving on to harder problems.

Reference excerpt

K2-141b (also designated EPIC 246393474.01) is a massive rocky exoplanet orbiting extremely close to a K Type orange main-sequence star K2-141. The planet was first discovered by the Kepler space telescope during its K2 “Second Light” mission and later observed by the HARPS-N spectrograph. It is classified as an ultra-short period planet (USP) and is confirmed to be terrestrial in nature. Its high density implies a massive iron core taking up between 30% and 50% of the planet's total mass.

Characteristics

Mass and radius Like the majority of known exoplanets, K2-141b was detected using the transit method, where a planet blocks a tiny fraction of its star's light as it passed between our line of the sight and its host. This method is only able to determine the radius of the planet, not its mass. However, K2-141b was also detected by the radial velocity method using the HARPS-N spectrograph. Therefore, its mass could also be determined along with its radius. The planet is classified as a Super-Earth, being significantly larger and more massive than Earth but not as large as the ice giants Uranus and Neptune. K2-141b has a radius of 1.51 R🜨, below the 1.6 R🜨 threshold where most planets are expected to accumulate thick hydrogen and helium atmospheres, transforming them into mini-Neptunes. The planet's mass confirms that it is rocky. It has a mass of 5.08 M🜨, which gives K2-141b a high density of 8.2 g/cm3, about 1.48 times the density of Earth. This high density implies a composition with a large iron core taking up about 30% to 50% of the planet's total mass.

Orbit K2-141b has one of the shortest known orbital periods of any confirmed exoplanet. With an orbital period of only 6.7 hours, it is the shortest-period planet known to date with a precisely determined mass. Only a few planets, including those around Kepler-70, have shorter orbital periods. At this proximity, K2-141b is most likely tidally locked with its host star, meaning that the same side of the planet always faces the star. It has a semi-major axis of 0.00716 +0.00055−0.00065 AU. For a comparison, Mercury's perihelion is 0.307499 AU, more than 41 times farther away from the Sun.

Atmosphere and climate Despite its terrestrial nature, K2-141b is far from habitable. Its extremely close proximity to its host star has resulted in an equilibrium temperature of about 2,039 K (1,766 °C; 3,211 °F). However, the actual temperature is probably much higher. About two-thirds of K2-141b faces perpetual daylight. The night side experiences frigid temperatures of below −200 °C (73.1 K; −328.0 °F). The day side of the exoplanet, at an estimated 3,000 °C (3,270 K; 5,430 °F), is hot enough to not only melt rocks but vaporize them as well. A low albedo of around 0.3 means most light which hits the planet is absorbed, adding to the heat of the dayside. K2-141b is believed to have both an atmosphere and oceans, which are magma and likely tens of kilometers deep. The makeup of the atmosphere is unknown but likely consists of vaporized metals which are common in solid form on Earth. The atmosphere is believed to have extreme wind speeds of over 1.75 kilometers per second. Temperatures are high enough that the magma in the oceans can vaporize into the atmosphere. The mineral vapor formed by evaporated rock is swept to the frigid night side by supersonic winds and rocks "rain" back down into a magma ocean. The resulting currents flow back to the hot day side of the exoplanet, where rock evaporates once more. If the planet's atmosphere has high levels of sodium, then solid sodium might slowly slide towards the planet's oceans, similarly to how glaciers move on Earth.

See also CoRoT-7b Kepler-10b Kepler-78b Lists of exoplanets List of directly imaged exoplanets List of largest exoplanets List of nearest exoplanets WASP-47e

References

Worked examples

Example 1 — a first encounter with K2-141b

Start with the simplest possible case. Write down what K2-141b 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 K2-141b 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 K2-141b 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 K2-141b

In research: K2-141b 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 K2-141b 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: K2-141b is common in secondary-school and first-year university syllabi. It links to neighbouring topics Exoplanets discovered by K2, Exoplanets discovered in 2018, Pisces (constellation), so understanding it makes those chapters shorter.
In everyday life: Look for K2-141b 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 K2-141b in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what K2-141b 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 K2-141b out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is K2-141b in simple terms?

Why does K2-141b 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 K2-141b?

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 K2-141b.