astronomy

HAT-P-2b

HAT-P-2b 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 HAT-P-2b rather than just read about it. In short: HAT-P-2b is an extrasolar planet detected by the HATNet Project in May 2007. It orbits a class F star HAT-P-2, (bigger and hotter than the Sun), located about 420 light-years away in the constellation Hercules.

Key takeaways

HAT-P-2b belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect HAT-P-2b to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of HAT-P-2b from memory before moving on to harder problems.

Reference excerpt

HAT-P-2b is an extrasolar planet detected by the HATNet Project in May 2007. It orbits a class F star HAT-P-2, (bigger and hotter than the Sun), located about 420 light-years away in the constellation Hercules. The planet is officially named Magor. The name was selected in the NameExoWorlds campaign by Hungary, during the 100th anniversary of the International Astronomical Union. Magor was a legendary ancestor of the Magyar people and the Hungarian nation, and brother of Hunor (name of the star HAT-P-2).

Physical properties The planet's mass has been estimated to be 8.7 times that of Jupiter, while its diameter is 1.157 times Jupiter's. Its small size, despite the bloating of the planet's atmosphere, is caused by the strong gravity of the planet. The planetary atmosphere has indeed the smallest scale height, equal to 26km, among exoplanets with measurable atmospheres as of 2021. This indicates its mean density is twice that of Earth and its surface gravity approximately 24 times that of Earth, almost equal to the Sun. In addition to heat from its primary star, tidal heating is thought to have played a significant role in this planet's evolution.

Orbit The planetary orbital period is 5 days 15 hours, and its inclination is such that it crosses directly in front of the star as viewed from Earth. The orbit is very eccentric, ranging from 4.90 million to 15.36 million miles from the star. As of August 2008, the most recent calculation of HAT-P-2b's Rossiter–McLaughlin effect and so spin-orbit angle was that of Winn in 2007 but Loeillet has in 2008 disputed it. For Winn, this is +1 ± 13 degrees. The study in 2012 determined the planetary orbit is probably aligned with the equatorial plane of the star, with misalignment equal to 9±10°.

Other planets in the system It has been suggested that there is a second outer planet perturbing HAT-P-2b. In 2023, the presence of a second planet, HAT-P-2c, was confirmed.

References

External links Media related to HAT-P-2b at Wikimedia Commons

The Extrasolar Planets Encyclopaedia The Israeli Team From Tel Aviv University

Illustrations

Worked examples

Example 1 — a first encounter with HAT-P-2b

Start with the simplest possible case. Write down what HAT-P-2b 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 HAT-P-2b 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 HAT-P-2b 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 HAT-P-2b

In research: HAT-P-2b 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 HAT-P-2b 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: HAT-P-2b is common in secondary-school and first-year university syllabi. It links to neighbouring topics Exoplanets discovered by HATNet, Exoplanets discovered in 2007, Exoplanets with proper names, so understanding it makes those chapters shorter.
In everyday life: Look for HAT-P-2b 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 HAT-P-2b in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what HAT-P-2b 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 HAT-P-2b out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is HAT-P-2b in simple terms?

Why does HAT-P-2b 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 HAT-P-2b?

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 HAT-P-2b.