astronomy

NGC 7549

NGC 7549 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 NGC 7549 rather than just read about it. In short: NGC 7549 is a peculiar barred spiral galaxy in the constellation of Pegasus. Its velocity with respect to the cosmic microwave background is 4,373±26 km/s, which corresponds to a Hubble distance of 210.4 ± 14.8 Mly (64.50 ± 4.53 Mpc).

Key takeaways

NGC 7549 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect NGC 7549 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of NGC 7549 from memory before moving on to harder problems.

Reference excerpt

NGC 7549 is a peculiar barred spiral galaxy in the constellation of Pegasus. Its velocity with respect to the cosmic microwave background is 4,373±26 km/s, which corresponds to a Hubble distance of 210.4 ± 14.8 Mly (64.50 ± 4.53 Mpc). However, five non-redshift measurements give a closer mean distance of 187.41 ± 14.74 Mly (57.460 ± 4.518 Mpc). It was discovered by Irish engineer Bindon Stoney on 2 November 1850. NGC 7549 has an active galactic nucleus, i.e. it has a compact region at the center of a galaxy that emits a significant amount of energy across the electromagnetic spectrum, with characteristics indicating that this luminosity is not produced by the stars.

Hickson Compact Group 93

NGC 7549 is a member of the Hickson Compact Group HCG 93. This five member group of galaxies also contains NGC 7547, NGC 7550, NGC 7553, and NGC 7558.

Arp 99 NGC 7549 along with NGC 7547 and NGC 7550 are listed together as Arp 99 in Halton Arp's Atlas of Peculiar Galaxies as Arp 99, as an example of spirals with companions attached to spiral arms.

Supernovae Two supernovae have been observed in NGC 7549:

SN 2009nq (Type Ia, mag. 16.2) was discovered by the Robotic Optical Transient Search Experiment (ROTSE) on 28 December 2009. SN 2019fya (Type II, mag. 16.3) was discovered by Kōichi Itagaki on 24 May 2019.

See also List of NGC objects (7001–7840)

References

External links Media related to NGC 7549 at Wikimedia Commons NGC 7549 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images

Illustrations

Worked examples

Example 1 — a first encounter with NGC 7549

Start with the simplest possible case. Write down what NGC 7549 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 NGC 7549 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 NGC 7549 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 NGC 7549

In research: NGC 7549 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 NGC 7549 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: NGC 7549 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Arp objects, Astronomical objects discovered in 1850, Barred spiral galaxies, so understanding it makes those chapters shorter.
In everyday life: Look for NGC 7549 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 NGC 7549 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what NGC 7549 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 NGC 7549 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is NGC 7549 in simple terms?

Why does NGC 7549 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 NGC 7549?

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 NGC 7549.