astronomy

WASP-19b

WASP-19b 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-19b rather than just read about it. In short: WASP-19b, formally named Banksia, is an exoplanet, notable for possessing one of the shortest orbital periods of any known planetary body: 0.79 days or approximately 18.932 hours. It has a mass close to that of Jupiter (1.15 Jupiter masses), but by comparison has a much larger radius (1.31 times that of Jupiter, or 0.13 Solar radii); making it nearly the size of a low-mass star.

Key takeaways

WASP-19b 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-19b to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of WASP-19b from memory before moving on to harder problems.

Reference excerpt

WASP-19b, formally named Banksia, is an exoplanet, notable for possessing one of the shortest orbital periods of any known planetary body: 0.79 days or approximately 18.932 hours. It has a mass close to that of Jupiter (1.15 Jupiter masses), but by comparison has a much larger radius (1.31 times that of Jupiter, or 0.13 Solar radii); making it nearly the size of a low-mass star. It orbits the star WASP-19 in the Vela constellation. At the time of discovery it was the shortest period hot Jupiter discovered as planets with shorter orbital periods had a rocky, or metallic composition. A study in 2012, utilizing the Rossiter–McLaughlin effect, determined the planetary orbit is well aligned with the equatorial plane of the star, misalignment equal to -15±11°. In 2013, secondary eclipse and orbital phases were barely observed from the data gathered with ASTEP telescope, making it the first detection of such kind through ground-based observations. This was possible due to the large size of the planet and its small semi-major axis. In 2019 the planet was observed with TESS and the eclipse of the planet was measured. The broad variations caused by the changing aspect of the heated face of the planet were measured. The study deduced that the dayside has a temperature of 2240 ± 40 K (1967 ± 40 °C) and that the planet reflects 16 ± 4 percent of the light that falls on it. The last value is relatively high compared to other planets. Despite the short orbital period, orbital decay of WASP-19b was not detected as of 2019.

Nomenclature In August 2022, this planet and its host star were included among 20 systems to be named by the third NameExoWorlds project. The approved names, proposed by a team from Brandon Park Primary School in Wheelers Hill (Melbourne, Australia), led by scientist Lance C. Kelly and teacher David Maierhofer were announced in June 2023. WASP-19b is named Banksia and its host star is named Wattle, after the Banksia and wattle plants.

Atmosphere In December 2013, scientists working with the Hubble Space Telescope reported detecting water in the atmosphere of the exoplanet. In September 2017, astronomers using the Very Large Telescope at the European Southern Observatory reported the detection of titanium oxide (TiO) in WASP-19b's atmosphere. This was the first time titanium oxide had been detected in an exoplanet atmosphere. They also detected a strongly scattering haze in the atmosphere as well as the element sodium, and additionally found the presence of water vapour. Strong haze and barely discernible titanium oxide signal were confirmed in 2021, while no sign of water or alkali metals could be found. The presence of water vapour was confirmed in a 2025 study with JWST, along with evidences for carbon monoxide, carbon dioxide, methane (CH4) and acetylene (C2H2). A study using TESS data concluded that the atmosphere of WASP-19b is moderately efficient at transporting heat from the dayside to the nightside.

References

External links Media related to WASP-19b at Wikimedia Commons

Illustrations

Worked examples

Example 1 — a first encounter with WASP-19b

Start with the simplest possible case. Write down what WASP-19b 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-19b 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-19b 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-19b

In research: WASP-19b 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-19b 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-19b is common in secondary-school and first-year university syllabi. It links to neighbouring topics Exoplanets discovered by WASP, Exoplanets discovered in 2009, Exoplanets with proper names, so understanding it makes those chapters shorter.
In everyday life: Look for WASP-19b 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-19b in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what WASP-19b 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-19b out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is WASP-19b in simple terms?

Why does WASP-19b 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-19b?

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-19b.