astronomy

NGC 1515

NGC 1515 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 1515 rather than just read about it. In short: NGC 1515 is a spiral galaxy in the constellation Dorado. The galaxy lies about 55 million light years away from Earth, which means, given its apparent dimensions, that NGC 1515 is approximately 100,000 light years across.

Key takeaways

NGC 1515 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 1515 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of NGC 1515 from memory before moving on to harder problems.

Reference excerpt

NGC 1515 is a spiral galaxy in the constellation Dorado. The galaxy lies about 55 million light years away from Earth, which means, given its apparent dimensions, that NGC 1515 is approximately 100,000 light years across. It was discovered by James Dunlop on November 5, 1826. It is a member of the Dorado Group.

Characteristics NGC 1515 is seen highly inclined. It has multiple spiral arms with fragments of dust lanes. The galactic nucleus is small, while the bulge seems to extend over the galactic plane. It is X-shaped (this shape is also referred to as peanut or box-shaped). There is evidence of a bar. Some HII regions are visible in the arms. The galaxy appears deficient in hydrogen. The total hydrogen mass is estimated to be 5.2×108 M☉, about ten times less than predicted. The hydrogen radius of the galaxy is 70% less than the optical one and there is no significant diffuse hydrogen emission around the galaxy. The galaxy probably lost most of its hydrogen as it passed through the centre of its galaxy group. In the centre of the galaxy is predicted to lie a supermassive black hole whose mass is estimated to be between 3.2 and 17 million solar masses, based on the spiral arm pitch angle.

Nearby galaxies NGC 1515 is a member of the Dorado Group, which consists of at least 46 members, and is part of the NGC 1566 subgroup. NGC 1515 is relatively isolated from the other members. A dwarf galaxy is located within 200 kiloparsecs. NGC 1515A lies 2 arcminutes away from the galaxy, however its redshift is about ten times higher and the pairing is just visual.

References

External links

NGC 1515 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 1515

Start with the simplest possible case. Write down what NGC 1515 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 1515 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 1515 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 1515

In research: NGC 1515 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 1515 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 1515 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Astronomical objects discovered in 1826, Discoveries by James Dunlop, Dorado, so understanding it makes those chapters shorter.
In everyday life: Look for NGC 1515 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 1515 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what NGC 1515 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 1515 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is NGC 1515 in simple terms?

Why does NGC 1515 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 1515?

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 1515.