astronomy

NGC 855

NGC 855 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 855 rather than just read about it. In short: NGC 855 is a star-forming dwarf elliptical galaxy located in the Triangulum constellation. The discovery and a first description (as H 26 613) was realized by William Herschel on 26 October 1786 and the findings made public through his Catalogue of Nebulae and Clusters of Stars, published the same year.

Key takeaways

NGC 855 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 855 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of NGC 855 from memory before moving on to harder problems.

Reference excerpt

NGC 855 is a star-forming dwarf elliptical galaxy located in the Triangulum constellation. The discovery and a first description (as H 26 613) was realized by William Herschel on 26 October 1786 and the findings made public through his Catalogue of Nebulae and Clusters of Stars, published the same year. NGC 855's relative velocity to the cosmic microwave background is 343 ± 18 km/s (343 ± 18) km/s, corresponding to a Hubble distance of 5.06 ± 0.44 Mpc (~16.5 million ly). There is some uncertainty about its precise distance since two surface brightness fluctuation measurements give a distance of 9.280 ± 0.636 Mpc (~30.3 million ly), a range outside the Hubble distance determined by the galaxy's redshift survey.

Star formation Using infrared data collected from two regions in the center of the galaxy by the Spitzer Space Telescope, astronomers were able to suggest NGC 855 to be a star-forming galaxy. Its HI distribution (Neutral atomic hydrogen emission lines) suggests the star-forming activity might have been triggered by a minor merger.

See also New General Catalogue List of NGC objects

References

External links NASA/IPAC Extragalactic Database - Extensive database of NGC objects.

Illustrations

Worked examples

Example 1 — a first encounter with NGC 855

Start with the simplest possible case. Write down what NGC 855 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 855 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 855 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 855

In research: NGC 855 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 855 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 855 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Astronomical objects discovered in 1786, Discoveries by William Herschel, Dwarf elliptical galaxies, so understanding it makes those chapters shorter.
In everyday life: Look for NGC 855 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 NGC 855 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what NGC 855 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 855 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is NGC 855 in simple terms?

Why does NGC 855 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 855?

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 855.