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astronomy

Sh 2-170

Sh 2-170 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 Sh 2-170 rather than just read about it. In short: Sharpless 2-170, also known by the common name the Little Rosette Nebula is an emission nebula in the constellation Cassiopeia. It was discovered by Stewart Sharpless in the late 1950s, and its discovery published in 1959.

Sh 2-170 — main illustration
Sh 2-170 — illustration

Key takeaways

  • Sh 2-170 belongs to astronomy; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect Sh 2-170 to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of Sh 2-170 from memory before moving on to harder problems.

Reference excerpt

Sharpless 2-170, also known by the common name the Little Rosette Nebula is an emission nebula in the constellation Cassiopeia. It was discovered by Stewart Sharpless in the late 1950s, and its discovery published in 1959. It is named after the larger, much more well known Rosette Nebula. It is located in the Perseus Arm of the Milky Way galaxy. Although being a separate nebula, it is considered as the dot in the Question Mark Nebula, as an extension of NGC 7822. The nebula contains a central star cluster, Stock 18. Stock 18, has an apparent size much smaller than the nebula's total of 56 x 50 arcminutes, with the cluster having an apparent size of just 18 arcminutes. Some of its illumination is caused by the ionizing of gas by the star BD + 63 2093, also designated LS I +64 11. There is dispute between studies as to the nature of said central star. A 1995 paper concluded the star was a O8 V type, however other papers have identified it as a O9 V type, and SIMBAD labels it as a G5 star. The nebula contains a total of 71 variable stars.

Visibility Sh 2-170 has a magnitude of about 6.5. It is best viewed with a hydrogen-alpha filter. Most of the nebula is faint enough that it requires a longer exposure time to be visible to cameras.

See also Rosette Nebula NGC 1624, the Little Cocoon Nebula

References

Illustrations

Sh 2-170 illustration

Worked examples

Example 1 — a first encounter with Sh 2-170

Start with the simplest possible case. Write down what Sh 2-170 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 Sh 2-170 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 Sh 2-170 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 Sh 2-170

In research
Sh 2-170 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 Sh 2-170 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
Sh 2-170 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Cassiopeia (constellation), Emission nebulae, H II regions, so understanding it makes those chapters shorter.
In everyday life
Look for Sh 2-170 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 Sh 2-170 in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Sh 2-170 means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Sh 2-170 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Sh 2-170 in simple terms?

Sharpless 2-170, also known by the common name the Little Rosette Nebula is an emission nebula in the constellation Cassiopeia. It was discovered by Stewart Sharpless in the late 1950s, and its discovery published in 1959.

Why does Sh 2-170 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 Sh 2-170?

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 Sh 2-170.

Tags

  • Cassiopeia (constellation)
  • Emission nebulae
  • H II regions
  • Sharpless objects

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