astronomy

Qatar-4

Qatar-4 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 Qatar-4 rather than just read about it. In short: Qatar-4 is a faint K-dwarf star that hosts a planet in the constellation Andromeda. With an apparent magnitude of 13.60, it is impossible to detect with the naked eye, but can be detected with a powerful telescope.

Key takeaways

Qatar-4 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Qatar-4 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Qatar-4 from memory before moving on to harder problems.

Reference excerpt

Qatar-4 is a faint K-dwarf star that hosts a planet in the constellation Andromeda. With an apparent magnitude of 13.60, it is impossible to detect with the naked eye, but can be detected with a powerful telescope. Qatar-4 is currently located 1,083 light years away based on parallax.

Properties This star is a relatively young star with an age of only 170 million years. At this age, it is still on the main sequence. Qatar-4 has 89.6% the mass of the Sun, and 84.9% the latter's radius. Despite all of this, it only has 48.1% of the Sun's luminosity, which corresponds to an effective temperature of 5,120 K. Qatar-4 has a similar metallicity to the Sun, and rotates at a rate of 7.1 km/s.

Planetary system In 2016, the Qatar Exoplanet Survey discovered a planet around this star.

Qatar-4b Qatar-4b is a Super-Jupiter orbiting the star Qatar-4 every 1.8 days. It was discovered in 2016 by the Qatar Exoplanet Survey (QES). This planet has a very short orbit, with only 1.8 days for it to complete an orbit around Qatar-4. The period corresponds with a separation of around 0.03 AU, which is almost 20 times closer than Mercury is to the Sun. Despite that, it has a perfectly round orbit. Since the host is an active star, Qatar-4 may be destroyed by tidal waves from the star. Qatar-4b has over 5 times the mass of Jupiter. Despite this, it has a radius that is only 13.5% larger than the latter's. This planet has an effective temperature of 1,385 K, which classifies as a hot Jupiter, and is denser than Jupiter, with about 4 times the density.

See also Qatar-1 Qatar-2 Qatar-3 Qatar-5

References

Worked examples

Example 1 — a first encounter with Qatar-4

Start with the simplest possible case. Write down what Qatar-4 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 Qatar-4 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 Qatar-4 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 Qatar-4

In research: Qatar-4 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 Qatar-4 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: Qatar-4 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Andromeda (constellation), K-type main-sequence stars, Planetary systems with one confirmed planet, so understanding it makes those chapters shorter.
In everyday life: Look for Qatar-4 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 Qatar-4 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Qatar-4 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 Qatar-4 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Qatar-4 in simple terms?

Why does Qatar-4 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 Qatar-4?

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 Qatar-4.