astronomy

Psi9 Aurigae

Psi9 Aurigae 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 Psi9 Aurigae rather than just read about it. In short: Psi9 Aurigae is a star in the northern constellation of Auriga. Its name is a Bayer designation that is Latinized from ψ9 Aurigae, and abbreviated Psi9 Aur or ψ9 Aur.

Key takeaways

Psi9 Aurigae belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Psi9 Aurigae to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Psi9 Aurigae from memory before moving on to harder problems.

Reference excerpt

Psi9 Aurigae is a star in the northern constellation of Auriga. Its name is a Bayer designation that is Latinized from ψ9 Aurigae, and abbreviated Psi9 Aur or ψ9 Aur. This star is dimly visible to the naked eye with an apparent visual magnitude of 5.75. Based upon an annual parallax shift of 3.45 mas, the distance to this star is approximately 950 light-years (290 parsecs). It is drifting closer to the Sun with a radial velocity of −41 km/s. This is most likely (88.5% chance) a runaway star, having a peculiar velocity of 31.8+14.6−12.4 km/s. The spectrum of Psi9 Aurigae matches a giant star with a stellar classification of B8 IIIe. The 'e' suffix indicates this is a Be star that shows emission lines of hydrogen in its spectrum. This is caused by a circumstellar shell of hot gas. The emission undergoes variability on a time scale of sixteen years. This star is spinning rapidly with a projected rotational velocity of 235 km/s. It has 2.4 times the mass of the Sun and 3.7 times the Sun's radius. ψ9 Aur is radiating 868 times the luminosity of the Sun from its photosphere at an effective temperature of 9,573 K.

References

External links HR 2568 Bright Star Catalog entry φ9 Aurigae image

Illustrations

Worked examples

Example 1 — a first encounter with Psi9 Aurigae

Start with the simplest possible case. Write down what Psi9 Aurigae 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 Psi9 Aurigae 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 Psi9 Aurigae 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 Psi9 Aurigae

In research: Psi9 Aurigae 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 Psi9 Aurigae 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: Psi9 Aurigae is common in secondary-school and first-year university syllabi. It links to neighbouring topics Auriga, B-type giants, Bayer objects, so understanding it makes those chapters shorter.
In everyday life: Look for Psi9 Aurigae 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.

Affiliate

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

How to study Psi9 Aurigae in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Psi9 Aurigae 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 Psi9 Aurigae out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Psi9 Aurigae in simple terms?

Psi9 Aurigae is a star in the northern constellation of Auriga. Its name is a Bayer designation that is Latinized from ψ9 Aurigae, and abbreviated Psi9 Aur or ψ9 Aur.

Why does Psi9 Aurigae 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 Psi9 Aurigae?

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 Psi9 Aurigae.