astronomy

NGC 5806

NGC 5806 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 5806 rather than just read about it. In short: NGC 5806 is an intermediate spiral galaxy in the constellation Virgo. It was discovered by German-British astronomer William Herschel on 24 February 1786.

Key takeaways

NGC 5806 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 5806 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of NGC 5806 from memory before moving on to harder problems.

Reference excerpt

NGC 5806 is an intermediate spiral galaxy in the constellation Virgo. It was discovered by German-British astronomer William Herschel on 24 February 1786. It is located about 70 million light-years (21 Megaparsecs) away from the Milky Way. It is a member of the NGC 5846 Group.

Supernovae and Imposter

Three supernovae and one supernova imposter have been observed in NGC 5806:

SN 2004dg (Type II, mag. 17.1) was discovered by Associazione Ternana Astrofili on 19 July 2004. The progenitor of SN 2004dg has not been detected and is expected to have been a relatively low mass, low luminosity, red supergiant. SN 2012P (Type IIb, mag. 15.0) was discovered by Fabio Briganti on 22 January 2012. Originally classified as a Type Ib/c, it was later determined to be Type IIb. Later analysis concluded that the progenitor had an initial mass of 15.2 M☉. iPTF13bvn (Type Ib, mag. 17.2) was discovered by the Palomar Transient Factory on 16 June 2013. SN Hunt 248 (also known as AT 2014ib) was discovered by the Catalina Real-time Transient Survey and Stan Howerton on 21 May 2014. It was initially catalogued as a supernova, but was later classified as a supernova imposter. The progenitor was detected as a cool hypergiant with an absolute visual magnitude of −9 and 400,000 times more luminous than the sun. The eruption saw it increase in luminosity to around 80,000,000 L☉. Later analysis concluded that this object is a luminous red nova.

References

External links Media related to NGC 5806 at Wikimedia Commons An LBV masquerading as a cool hypergiant ESA/Hubble Picture of the Week showing SN 2004dg

Illustrations

Worked examples

Example 1 — a first encounter with NGC 5806

Start with the simplest possible case. Write down what NGC 5806 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 5806 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 5806 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 5806

In research: NGC 5806 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 5806 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 5806 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Astronomical objects discovered in 1786, Discoveries by John Herschel, Intermediate spiral galaxies, so understanding it makes those chapters shorter.
In everyday life: Look for NGC 5806 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 5806 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what NGC 5806 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 5806 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is NGC 5806 in simple terms?

NGC 5806 is an intermediate spiral galaxy in the constellation Virgo. It was discovered by German-British astronomer William Herschel on 24 February 1786.

Why does NGC 5806 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 5806?

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 5806.