astronomy

HD 113538

HD 113538 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 HD 113538 rather than just read about it. In short: HD 113538 (Gliese 496.1) is a star with two planetary companions in the southern constellation of Centaurus. It is much too faint to be viewed with the naked eye at an apparent visual magnitude of 9.05.

Key takeaways

HD 113538 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect HD 113538 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of HD 113538 from memory before moving on to harder problems.

Reference excerpt

HD 113538 (Gliese 496.1) is a star with two planetary companions in the southern constellation of Centaurus. It is much too faint to be viewed with the naked eye at an apparent visual magnitude of 9.05. The distance to this star is 53 light years and it is drifting further away with a radial velocity of +39 km/s. This is a K-type main-sequence star of a late spectral type, classified as K9Vk:. It displays chromospheric activity with a stellar cycle of at least four years and is metal poor. The star has 58.5% of the mass and 53% of the radius of the Sun. It is radiating just 12.7% of the luminosity of the Sun from its photosphere at an effective temperature of 4,462 K.

Planetary system Radial velocity variation of HD 113538 was inferred from observations with the HARPS spectrograph. The star is active (Log R'HK −4.697, SMW 1.05), but the RV variation is not correlated with activity, indicating that planets are responsible. The data is fitted well by a solution including two planets, with an eccentric Saturn-mass planet and a more massive planet on a longer-period orbit—similar to the orbital architecture of the planetary system orbiting HD 163607, though with lower masses. Similar to HD 163607 b, the eccentricity and argument of periastron of HD 113538 b increases the planet's transit probability substantially more than it would be on a circular orbit.

References

Worked examples

Example 1 — a first encounter with HD 113538

Start with the simplest possible case. Write down what HD 113538 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 HD 113538 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 HD 113538 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 HD 113538

In research: HD 113538 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 HD 113538 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: HD 113538 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Centaurus, Durchmusterung objects, Gliese and GJ objects, so understanding it makes those chapters shorter.
In everyday life: Look for HD 113538 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 HD 113538 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what HD 113538 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 HD 113538 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is HD 113538 in simple terms?

Why does HD 113538 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 HD 113538?

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 HD 113538.