astronomy

Tau Orionis

Tau Orionis 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 Tau Orionis rather than just read about it. In short: Tau Orionis (τ Ori, τ Orionis) is a binary star in the constellation Orion. If an imaginary line is drawn north-west between the stars Rigel and Mintaka, Tau Orionis can be found roughly one-sixth of the way to Mintaka.

Key takeaways

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

Reference excerpt

Tau Orionis (τ Ori, τ Orionis) is a binary star in the constellation Orion. If an imaginary line is drawn north-west between the stars Rigel and Mintaka, Tau Orionis can be found roughly one-sixth of the way to Mintaka. It is visible to the naked eye with a combined apparent visual magnitude of 3.58. Based upon an annual parallax shift of 6.6 mas, it is located around 490 light years distant. This is a spectroscopic binary system with an orbital period of 90 days and a very high eccentricity of 0.834. It is a heartbeat star, showing variations on its apparent magnitude during the close periastron passage. The components have equal masses of 6 M☉ and a combined stellar classification of B5 III. The star has a peculiar velocity through space of 16.9 km/s. Tau Orionis has three visual companions: magnitude 11.0 component B at an angular separation of 33.30″ along a position angle of 251°; magnitude 10.9 component C lying some 3.80″ from component B; and magnitude 10.9 component D at 36.0″ from τ Ori along a position angle of 51°, all as of 2011.

Proper names According to Richard H. Allen, this star, along with β Eri, λ Eri and ψ Eri were Al Kursiyy al Jauzah, "the Chair (or "Footstool") of the Central One". However, per the catalogue of stars in the Technical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars, Al Kursiyy al Jauzah were the title for just three stars: β Eri as Cursa, ψ Eri as Al Kursiyy al Jauzah I and λ Eri as Al Kursiyy al Jauzah II, excluding this star. In Chinese, 玉井 (Yù Jǐng), meaning Jade Well, refers to an asterism consisting of τ Orionis, β Eridani, λ Eridani and ψ Eridani. Consequently, the Chinese name for τ Orionis itself is 玉井四 (Yù Jǐng sì, English: the Fourth Star of Jade Well.). From this Chinese title, the name Yuh Tsing is derived.

References

External links Kaler, James B. (January 23, 2009), "Tau Orionis", Stars, University of Illinois, retrieved 2016-11-18.

Illustrations

Worked examples

Example 1 — a first encounter with Tau Orionis

Start with the simplest possible case. Write down what Tau Orionis 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 Tau Orionis 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 Tau Orionis 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 Tau Orionis

In research: Tau Orionis 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 Tau Orionis 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: Tau Orionis is common in secondary-school and first-year university syllabi. It links to neighbouring topics B-type giants, Bayer objects, Bright Star Catalogue objects, so understanding it makes those chapters shorter.
In everyday life: Look for Tau Orionis 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 Tau Orionis in 20 minutes

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

Frequently asked questions

What is Tau Orionis in simple terms?

Why does Tau Orionis 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 Tau Orionis?

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 Tau Orionis.