astronomy

NGC 1142

NGC 1142 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 1142 rather than just read about it. In short: NGC 1142 (also known as NGC 1144) is a distorted spiral galaxy in the constellation of Cetus. It is located about 370 million light years away from Earth, NGC 1142 is approximately 420,000 light years across.

Key takeaways

NGC 1142 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 1142 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of NGC 1142 from memory before moving on to harder problems.

Reference excerpt

NGC 1142 (also known as NGC 1144) is a distorted spiral galaxy in the constellation of Cetus. It is located about 370 million light years away from Earth, NGC 1142 is approximately 420,000 light years across. It is a type 2 Seyfert galaxy. It interacts with the elliptical galaxy NGC 1141. It was discovered by Albert Marth on October 5, 1864, who noted a location 40 arcminutes north of the real location, and it was discovered independently on November 17, 1876, by Édouard Stephan.

Characteristics NGC 1142 is a spiral galaxy which interacts with the elliptical galaxy NGC 1141. The linear separation of the two galaxies is 40 arcseconds, which corresponds to about 20 kiloparsecs at the distance of NGC 1142. The closest encounter took place 22 million years before the observed moment and created a density wave across NGC 1142, which resulted in the formation of knots of gas and stars, and led to the distortion of the spiral galaxy, creating a knotty loop or ring that extends towards NGC 1141 and an off-centre nucleus. A stellar bridge connects the two galaxies. The total infrared luminosity of the galaxy is 2.2×1011 L☉, and thus it is categorised as a luminous infrared galaxy. Much of the mid-infrared emission originates from a massive extra-nuclear star formation region. Very large star clusters, categorised as super star clusters, have been formed in the loops, as a result of the increased gas density created by the density waves of the impact. The gas dynamics in the galaxy are characterised by the very large velocity range, which is up to 1,100 m/s for the CO emission. NGC 1142 is one of the most luminous galaxies in the local universe as far as CO emission is concerned, twice as bright as the merger remnant Arp 220. Most of the emission originates from the ring, and especially its southern part, and a giant HII region west of the nucleus. The nucleus of NGC 1142 has been found to be active and it has been categorised as a type II Seyfert galaxy. The most accepted theory for the energy source of active galactic nuclei is the presence of an accretion disk around a supermassive black hole. The mass of the black hole in the centre of NGC 1142 is estimated to be 10(8.40 ± 0.21) (155–410 million) M☉.

See also Eyes Galaxies – a similar pair of interacting galaxies

References

External links

NGC 1142 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images NGC 1142 on SIMBAD

Illustrations

Worked examples

Example 1 — a first encounter with NGC 1142

Start with the simplest possible case. Write down what NGC 1142 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 1142 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 1142 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 1142

In research: NGC 1142 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 1142 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 1142 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Arp objects, Astronomical objects discovered in 1864, Cetus (constellation), so understanding it makes those chapters shorter.
In everyday life: Look for NGC 1142 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 1142 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what NGC 1142 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 1142 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is NGC 1142 in simple terms?

Why does NGC 1142 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 1142?

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 1142.