astronomy

SN 1917A

SN 1917A 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 SN 1917A rather than just read about it. In short: SN 1917A is a supernova event in the Fireworks Galaxy (NGC 6946), positioned 37″ west and 105″ south of the galactic core. Discovered by American optician George Willis Ritchey on 19 July 1917, it reached a peak visual magnitude of 13.6.

Key takeaways

SN 1917A belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect SN 1917A to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of SN 1917A from memory before moving on to harder problems.

Reference excerpt

SN 1917A is a supernova event in the Fireworks Galaxy (NGC 6946), positioned 37″ west and 105″ south of the galactic core. Discovered by American optician George Willis Ritchey on 19 July 1917, it reached a peak visual magnitude of 13.6. Based on a poor quality photographic spectrum taken at least a month after peak light by F. G. Pease and Ritchey, it was identified as a type II core-collapse supernova. A 2018 analysis of the surrounding stellar population by B. F. Williams suggests the progenitor star was most likely 13+13−1 million years old with 15+1−5 times the mass of the Sun (M☉). B. Koplitz and associates in 2021 inferred a progenitor mass estimate of 9.3+16.7−0.7 M☉. A 2020 search for light echoes from the supernova was unsuccessful.

References

Illustrations

Worked examples

Example 1 — a first encounter with SN 1917A

Start with the simplest possible case. Write down what SN 1917A 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 SN 1917A 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 SN 1917A 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 SN 1917A

In research: SN 1917A 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 SN 1917A 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: SN 1917A is common in secondary-school and first-year university syllabi. It links to neighbouring topics Astronomical objects discovered in 1917, Cepheus (constellation), Type II supernovae, so understanding it makes those chapters shorter.
In everyday life: Look for SN 1917A 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 “SN 1917A” →

Affiliate

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

How to study SN 1917A in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what SN 1917A 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 SN 1917A out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is SN 1917A in simple terms?

Why does SN 1917A 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 SN 1917A?

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 SN 1917A.