astronomy

HD 136164

HD 136164 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 136164 rather than just read about it. In short: HD 136164, also known as HIP 75056, is a binary star system in the constellation Lupus. At an apparent magnitude of +7.76, it is far too faint to be visible to the naked eye.

Key takeaways

HD 136164 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 136164 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of HD 136164 from memory before moving on to harder problems.

Reference excerpt

HD 136164, also known as HIP 75056, is a binary star system in the constellation Lupus. At an apparent magnitude of +7.76, it is far too faint to be visible to the naked eye. Parallax measurements give a distance of 398 light-years (121.9 parsecs). The primary is orbited by a brown dwarf.

Characteristics This is a visual binary system whose components, as of 2015, are separated by 5.195" in the sky, translating to a projected separation of 650 astronomical units. The orbital period is estimated at 8,000 years. The system is 16 million years old and is part of the Upper–Centaurus–Lupus stellar association. The primary component, HD 136164 A, has a spectrum matching a spectral class of A2V, with the luminosity class 'V' indicating it is a main sequence star fusing atoms of hydrogen into helium at its core. The star has 1.87 times the mass and 1.66 times the radius of the Sun. It radiates 12.65 times the Sun's luminosity from its photosphere at an effective temperature of 8,100 K. This temperature gives it the white hue typical of an A-type stars. The secondary has a mass of 0.30 M☉.

Substellar companion The primary star is orbited by a brown dwarf named HD 136164 Ab or HIP 75056 Ab. It was first discovered in 2020 through direct imaging. The companion orbits at a semi-major axis of 22.5 astronomical units, has a mild eccentricity, and takes roughly 130 years to circle the host star. Relative to Earth, the orbit is nearly face-on, with an inclination less than 35°. Based on observations of the brown dwarf's orbit using both relative and absolute astrometry, its mass is measured at 35±10 Jupiter masses. Comparing its spectrum to atmospheric models retrieve a radius of 1.9 RJ and an effective temperature of 2,640 K. The luminosity is estimated at 10−2.68+0.08−0.05 L☉ from evolutionary models. The carbon-to-oxygen abundance ratio and relatively high eccentricity of the orbit suggest that the companion formed like a failed star, either via fragmentation of the circumstellar disk or via fragmentation of a molecular cloud.

References

Worked examples

Example 1 — a first encounter with HD 136164

Start with the simplest possible case. Write down what HD 136164 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 136164 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 136164 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 136164

In research: HD 136164 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 136164 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 136164 is common in secondary-school and first-year university syllabi. It links to neighbouring topics A-type main-sequence stars, Brown dwarfs, Durchmusterung objects, so understanding it makes those chapters shorter.
In everyday life: Look for HD 136164 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.

Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “HD 136164” →

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study HD 136164 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what HD 136164 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 136164 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is HD 136164 in simple terms?

HD 136164, also known as HIP 75056, is a binary star system in the constellation Lupus. At an apparent magnitude of +7.76, it is far too faint to be visible to the naked eye.

Why does HD 136164 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 136164?

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 136164.