astronomy

HD 164509

HD 164509 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 164509 rather than just read about it. In short: HD 164509 is a binary star system in the constellation of Ophiuchus. The primary component has an orbiting exoplanet companion.

Key takeaways

HD 164509 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 164509 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of HD 164509 from memory before moving on to harder problems.

Reference excerpt

HD 164509 is a binary star system in the constellation of Ophiuchus. The primary component has an orbiting exoplanet companion. This system is located at a distance of 175 light years based on parallax measurements, and is drifting further away with a radial velocity of 13.7 km/s. It has an absolute magnitude of 4.64, but at that distance the system has an apparent visual magnitude of 8.10, which is too faint to be seen with the naked eye. The primary component is a Sun-like G-type main-sequence star with a stellar classification of G2V. It is young and metal rich, having heavy elements abundance 160% of solar. The star has a modest level of magnetic activity in its chromosphere. It has 1.10 times the mass of the Sun and 1.04 times the Sun's radius. This star is radiating 1.15 times the luminosity of the Sun from its photosphere at an effective temperature of 5,865 K. Initially it was thought the system consisted of a single star, but in 2016 it was discovered the primary is accompanied by the M-class red dwarf star at a projected separation of 36.5±1.9 AU. The evidence for this stellar companion being on a bound orbit was further fortified in 2017.

Planetary system

In 2011, a gas giant, HD 164509 Ab, was discovered orbiting the primary of HD 164509 using Doppler spectroscopy. Given the binary nature of this system, the planet HD 164509 Ab could not have formed on the current orbit, which is unstable in long term. Instead, it may be a captured body formed elsewhere.

References

Worked examples

Example 1 — a first encounter with HD 164509

Start with the simplest possible case. Write down what HD 164509 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 164509 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 164509 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 164509

In research: HD 164509 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 164509 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 164509 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Binary stars, G-type main-sequence stars, Henry Draper Catalogue objects, so understanding it makes those chapters shorter.
In everyday life: Look for HD 164509 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 164509 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what HD 164509 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 164509 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is HD 164509 in simple terms?

HD 164509 is a binary star system in the constellation of Ophiuchus. The primary component has an orbiting exoplanet companion.

Why does HD 164509 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 164509?

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 164509.