astronomy

NGC 3169

NGC 3169 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 3169 rather than just read about it. In short: NGC 3169 is a spiral galaxy about 75 million light years away in the constellation Sextans. It has the morphological classification SA(s)a pec, which indicates this is a pure, unbarred spiral galaxy with tightly-wound arms and peculiar features.

Key takeaways

NGC 3169 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 3169 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of NGC 3169 from memory before moving on to harder problems.

Reference excerpt

NGC 3169 is a spiral galaxy about 75 million light years away in the constellation Sextans. It has the morphological classification SA(s)a pec, which indicates this is a pure, unbarred spiral galaxy with tightly-wound arms and peculiar features. There is an asymmetrical spiral arm and an extended halo around the galaxy. It is a member of the NGC 3166 Group of galaxies, which is a member of the Leo II Groups, a series of galaxies and galaxy clusters strung out from the right edge of the Virgo Supercluster. This is a LINER 2 galaxy that displays an extended emission of X-rays in the region of the nucleus. A hard X-ray source at the center most likely indicates an active galactic nucleus. The stellar population in the nucleus, and a ring at an angular radius of 6″, shows an age of only one billion years and is generally younger than the surrounding stellar population. This suggests that a burst of star formation took place in the nucleus roughly one billion years ago. NGC 3169 is located in close physical proximity to NGC 3166, and the two have an estimated separation of around 160 kly (50 kpc). Their interaction is creating a gravitational distortion that has left the disk of NGC 3166 warped. Combined with NGC 3156, the three galaxies form a small group within the larger Leo 1 group. The three are embedded within an extended ring of neutral hydrogen that is centered on NGC 3169.

Supernovae Two supernovae have been observed in NGC 3169:

SN 1984E (Type II-L, mag. 14.5) was codiscovered by Nataliya Metlova on 26 March 1984, and by Robert Evans on 29 March 1984. The spectrum of this event at maximum light showed prominent Balmer lines that indicated the explosion occurred inside a dense shell of hydrogen surrounding the star. This shell was likely created by a strong stellar wind from the progenitor star. SN 2003cg (Type Ia, mag. 14.4) was codiscovered by Kōichi Itagaki and Ron Arbour on 21 March 2003.

References

External links

APOD: NGC 3169 and NGC 3166 (02/28/2004) Archived 2015-05-11 at the Wayback Machine ADS: Supernova 2003cg in NGC 3169 SEDS: NGC3169

NGC 3169 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 3169

Start with the simplest possible case. Write down what NGC 3169 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 3169 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 3169 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 3169

In research: NGC 3169 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 3169 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 3169 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Astronomical objects discovered in 1783, IRAS catalogue objects, MCG objects, so understanding it makes those chapters shorter.
In everyday life: Look for NGC 3169 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 3169 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what NGC 3169 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 3169 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is NGC 3169 in simple terms?

Why does NGC 3169 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 3169?

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 3169.