astronomy

WASP-31b

WASP-31b 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 WASP-31b rather than just read about it. In short: WASP-31b is a low-density (puffy) "hot Jupiter" extrasolar planet orbiting the metal-poor (63% of solar metallicity) dwarf star WASP-31. The exoplanet was discovered in 2010 by the WASP project.

Key takeaways

WASP-31b belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect WASP-31b to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of WASP-31b from memory before moving on to harder problems.

Reference excerpt

WASP-31b is a low-density (puffy) "hot Jupiter" extrasolar planet orbiting the metal-poor (63% of solar metallicity) dwarf star WASP-31. The exoplanet was discovered in 2010 by the WASP project. WASP-31b is in the constellation of Crater, and is about 1305 light-years (light travel distance) from Earth.

Characteristics WASP-31b is a low-density (puffy) "hot Jupiter" exoplanet with a mass about 0.48 times that of Jupiter and a radius about 1.55 times that of Jupiter. The planetary atmosphere has indeed the largest scale height, equal to 1150km, among exoplanets with measurable atmospheres as at 2021. The exoplanet orbits WASP-31, its host star, every 3.4 days.

In 2012, it was found from the Rossiter–McLaughlin effect that WASP-31b is orbiting the parent star in a prograde direction. The projected inclination of the WASP-31 star rotational axis relative to the planetary orbit is close to zero, with a value of −0.09+0.31−0.32 degrees cited in a 2026 study. The spectroscopic study in 2014 revealed that WASP-31b has a dense cloud deck overlaid by a hazy atmosphere. WASP-31b was also reported to have significant amounts of potassium in its upper atmosphere, but the detection of potassium was refuted in 2015. The potassium detection discrepancy was resolved in 2020 with the improved cloud deck model, with the best fit being a very small amount of water over clouds and no potassium at all. Reanalysis of planetary spectroscopic data in 2020 has revealed the presence of chromium monohydride besides water.

See also WASP-6b WASP-12b WASP-17b WASP-19b WASP-39b WASP-121b

References

External links Media related to WASP-31b at Wikimedia Commons

Illustrations

Worked examples

Example 1 — a first encounter with WASP-31b

Start with the simplest possible case. Write down what WASP-31b 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 WASP-31b 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 WASP-31b 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 WASP-31b

In research: WASP-31b 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 WASP-31b 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: WASP-31b is common in secondary-school and first-year university syllabi. It links to neighbouring topics Crater (constellation), Exoplanets discovered by WASP, Exoplanets discovered in 2010, so understanding it makes those chapters shorter.
In everyday life: Look for WASP-31b 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 WASP-31b in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what WASP-31b 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 WASP-31b out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is WASP-31b in simple terms?

WASP-31b is a low-density (puffy) "hot Jupiter" extrasolar planet orbiting the metal-poor (63% of solar metallicity) dwarf star WASP-31. The exoplanet was discovered in 2010 by the WASP project.

Why does WASP-31b 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 WASP-31b?

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 WASP-31b.