astronomy

NGC 985

NGC 985 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 985 rather than just read about it. In short: NGC 985 is a ring galaxy in the constellation of Cetus. It is located about 550 million light years away from Earth, which means, given its apparent dimensions, that NGC 985 is approximately 160,000 light years across.

Key takeaways

NGC 985 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 985 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of NGC 985 from memory before moving on to harder problems.

Reference excerpt

NGC 985 is a ring galaxy in the constellation of Cetus. It is located about 550 million light years away from Earth, which means, given its apparent dimensions, that NGC 985 is approximately 160,000 light years across. It was discovered by Francis Leavenworth in 1886. It is a type 1 Seyfert galaxy. NGC 985 is characterised by its ring shape. It is believed it was formed as a result of a galaxy merger. Further evidence supporting this theory is the observation of a second nucleus in NGC 985. When observed in infrared light, a second nucleus was found 3.8 arcseconds northwest of the active nucleus. It is much redder than the rest of the galaxy, indicating the presence of old stars. It has been suggested that the collision between a disk galaxy with another galaxy caused the formation of the ring and displaced the nucleus of the galaxy, creating an empty ring. Based on the kinematics of the galaxy, the secondary nucleus belonged to the intruder galaxy, while the active nucleus is associated with the main stellar component. As is common with merger remnants, NGC 985 has increased star formation rate, and as a result shines bright in the infrared. The total infrared luminosity of NGC 985 is 1.8×1011 L☉ and it is characterised as a luminous infrared galaxy. The total molecular gas mass of the galaxy is estimated to be 2×1010 M☉. Very large molecular clouds exist near the nuclei. They may be clouds gathering around the nucleus in the process of forming a disk around the two nuclei or molecular clouds disrupted by an outflow from the nucleus of the galaxy. NGC 985 is a powerful X-ray source, detected by ROSAT. It is a complex X-ray source, whose spectrum cannot be accounted for by a simple power law at 0.6 keV and suggests the presence of a warm absorber. The hard X-ray emission on the other hand is characterised by a simple power law. The X-ray flux, especially soft X-rays, diminished in NGC 985 in 2013. The variability of the X-ray and ultraviolet emission from the nucleus was observed using the XMM-Newton and Hubble Space Telescope respectively. These observations revealed the presence of outflowing wind from an accretion disk formed around a supermassive black hole that obstructed the nucleus in soft X-rays and UV. The nucleus is otherwise seen unobstructed.

References

External links

NGC 985 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images NGC 985 on SIMBAD

Illustrations

Worked examples

Example 1 — a first encounter with NGC 985

Start with the simplest possible case. Write down what NGC 985 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 985 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 985 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 985

In research: NGC 985 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 985 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 985 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Astronomical objects discovered in 1886, Cetus (constellation), Discoveries by Francis Leavenworth, so understanding it makes those chapters shorter.
In everyday life: Look for NGC 985 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 985 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what NGC 985 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 985 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is NGC 985 in simple terms?

Why does NGC 985 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 985?

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 985.