astronomy

NGC 1309

NGC 1309 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 1309 rather than just read about it. In short: NGC 1309 is a spiral galaxy located approximately 120 million light-years away, appearing in the constellation Eridanus. It was discovered by German-British astronomer William Herschel on 3 October 1785.

Key takeaways

NGC 1309 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 1309 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of NGC 1309 from memory before moving on to harder problems.

Reference excerpt

NGC 1309 is a spiral galaxy located approximately 120 million light-years away, appearing in the constellation Eridanus. It was discovered by German-British astronomer William Herschel on 3 October 1785. NGC 1309 is about 75,000 light-years across, and is about 3/4s the width of the Milky Way. Its shape is classified as SA(s)bc, meaning that it has moderately wound spiral arms and no ring. Bright blue areas of star formation can be seen in the spiral arms, while the yellowish central nucleus contains older-population stars. NGC 1309 is one of over 200 members of the Eridanus Group of galaxies.

NGC 1309 group NGC 1309 is the brightest member of a trio of galaxies named after it. The other two galaxies in the NGC 1309 group (also known as LGG 92) are MCG -03-09-027 and UGCA 71.

Supernovae Two supernovae have been observed in NGC 1309:

SN 2002fk (Type Ia, mag. 15) was discovered jointly by Reiki Kushida of the Yatsugatake South Base Observatory, Nagano Prefecture, Japan; and Jun-jie Wang and Yu-Lei Qiu of the Beijing Astronomical Observatory on 17 Sept 2002. It was estimated to have reached maximum magnitude of ~13.0 before fading away. SN 2002fk's spectra showed no indications of hydrogen, helium or carbon; instead ionized calcium, silicon, iron and nickel were found.

SN 2012Z (Type Iax, mag. 17.6) was discovered jointly by Brad Cenko, Weidong Li, and Alex Filippenko using the Katzman Automatic Imaging Telescope on 29 January 2012 as part of the Lick Observatory Supernova Search. The scientists have hypothesized that this is a Type Iax supernova, and may have left behind a remnant zombie star. In February 2022, a study with new observations has confirmed that the star survived the explosion and is even brighter than before.

See also List of NGC objects (1001–2000)

References

External links Media related to NGC 1309 at Wikimedia Commons

Illustrations

Worked examples

Example 1 — a first encounter with NGC 1309

Start with the simplest possible case. Write down what NGC 1309 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 1309 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 1309 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 1309

In research: NGC 1309 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 1309 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 1309 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Astronomical objects discovered in 1785, Discoveries by William Herschel, Eridanus (constellation), so understanding it makes those chapters shorter.
In everyday life: Look for NGC 1309 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 1309 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what NGC 1309 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 1309 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is NGC 1309 in simple terms?

Why does NGC 1309 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 1309?

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 1309.