astronomy

Tau Aquilae

Tau Aquilae 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 Aquilae rather than just read about it. In short: Tau Aquilae is a star in the equatorial constellation of Aquila. Its identifier is a Bayer designation that is Latinized from τ Aquilae, and abbreviated Tau Aql or τ Aql.

Key takeaways

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

Reference excerpt

Tau Aquilae is a star in the equatorial constellation of Aquila. Its identifier is a Bayer designation that is Latinized from τ Aquilae, and abbreviated Tau Aql or τ Aql. The star has the proper name Tianfu, after a traditional Chinese constellation. An apparent visual magnitude of 5.7 indicates it is a faint star that is visible to the naked eye from dark suburban skies; at least according to the Bortle Dark-Sky Scale. The annual orbital motion of the Earth causes a parallax shift of 6.1 mas, which means the distance to this star is approximately 535 light-years (164 parsecs). The magnitude of the star is diminished by 0.28 from extinction caused by interstellar gas and dust. It is drifting closer to the Sun with a radial velocity of −29 km/s. The spectrum of Tau Aquilae matches a stellar classification of K0 III, with the luminosity class of III suggesting this is an evolved giant star that has exhausted the supply of hydrogen at its core and left the main sequence of stars like the Sun. At an estimated age of one billion years, stellar models give a 90% chance that it is currently on the horizontal branch and is fusing helium at the core. Based on this assumption, it has 2.15 times the mass of the Sun and has expanded to 18 times the Sun's girth. The outer envelope is radiating energy into space with an effective temperature of 4,660 K, giving it the orange hued glow of a K-type star. Tianfu (天桴) was an ancient Chinese constellation consisting of four stars. τ Aquilae was the first star of an early version of this constellation, before the Tang dynasty. The IAU Working Group on Star Names approved the name Tianfu for this star on May 16, 2024 and it is now so entered in the IAU Catalog of Star Names. (See also θ Aquilae.)

References

External links Image Tau Aquilae

Illustrations

Worked examples

Example 1 — a first encounter with Tau Aquilae

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

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

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

Frequently asked questions

What is Tau Aquilae in simple terms?

Tau Aquilae is a star in the equatorial constellation of Aquila. Its identifier is a Bayer designation that is Latinized from τ Aquilae, and abbreviated Tau Aql or τ Aql.

Why does Tau Aquilae 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 Aquilae?

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 Aquilae.