astronomy

NGC 877

NGC 877 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 877 rather than just read about it. In short: NGC 877 is an intermediate spiral galaxy located in the constellation Aries. It is located at a distance of circa 160 million light years from Earth, which, given its apparent dimensions, means that NGC 877 is about 115,000 light years across.

Key takeaways

NGC 877 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 877 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of NGC 877 from memory before moving on to harder problems.

Reference excerpt

NGC 877 is an intermediate spiral galaxy located in the constellation Aries. It is located at a distance of circa 160 million light years from Earth, which, given its apparent dimensions, means that NGC 877 is about 115,000 light years across. It was discovered by William Herschel on October 14, 1784. It interacts with NGC 876. NGC 877 features two spiral arms with a grand design pattern and slightly disturbed morphology. When pictured in H-alpha, the arms have numerous knots and appear brighter than the nucleus. The northwest part of the galaxy has higher polarised emission than the rest of the galaxy. A bar appears in radio waves. The nucleus has activity that resembles that of a HII region. The galaxy has been categorised as a luminous infrared galaxy, a category of galaxies associated with high star formation rate. The total infrared luminosity of the galaxy is estimated to be between 1011.04 L☉ and 1011.1 L☉, lying near the threshold to classify a galaxy as luminous infrared. The total star formation rate in NGC 877 is estimated to be between 20 and 53 M☉ per year. NGC 877 forms a pair with the edge-on spiral galaxy NGC 876, which lies 2.1 arcminutes to the southwest. At the distance of NGC 877, this corresponds to a projected distance of 30 kpc. A low surface brightness bridge connects the two galaxies. NGC 870 and NGC 871 are two other nearby galaxies. NGC 877 is the brightest and most massive member of a galaxy group known as the NGC 877 group or LGG (Lyon Groups of Galaxies) 53. Other members of the group include NGC 876 and NGC 871, as well as UGC 1693, IC 1791, UGC 1773, and UGC 1817. The group contains large amounts of HI gas. During the October 2050 lunar eclipse, a Total Lunar Eclipse, it will be occulted by the Moon over the southeast Pacific Ocean, South America and the Atlantic Ocean. This will happen again during the October 2069 lunar eclipse over the northern half of Asia and the Northwest Pacific.

Supernova One supernova has been observed in NGC 877.

SN 2019rn (Type IIb, mag. 18.86) was discovered by the robotic sky survey ATLAS on January 12.30, 2019, using a twin 0.5m telescope system. The supernova was initially classified as a Type II supernova with spectroscopic observations by Keck-II, but further spectrographic observations categorized it as Type IIb.

Gallery

References

External links

NGC 877 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images NGC 877 on SIMBAD

Illustrations

Worked examples

Example 1 — a first encounter with NGC 877

Start with the simplest possible case. Write down what NGC 877 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 877 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 877 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 877

In research: NGC 877 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 877 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 877 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Aries (constellation), Astronomical objects discovered in 1784, Discoveries by William Herschel, so understanding it makes those chapters shorter.
In everyday life: Look for NGC 877 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 877 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what NGC 877 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 877 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is NGC 877 in simple terms?

Why does NGC 877 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 877?

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 877.