astronomy

NGC 3801

NGC 3801 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 3801 rather than just read about it. In short: NGC 3801 is a lenticular galaxy located in the constellation Leo. It is about 150 million light years from Earth, and estimated to be about 170,000 light years in diameter.

Key takeaways

NGC 3801 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 3801 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of NGC 3801 from memory before moving on to harder problems.

Reference excerpt

NGC 3801 is a lenticular galaxy located in the constellation Leo. It is about 150 million light years from Earth, and estimated to be about 170,000 light years in diameter. William Herschel discovered it on 17 April 1784.

Characteristics The morphology of NGC 3801 is disturbed, indicating that the galaxy underwent a merger with another gas rich galaxy. A dust lane runs across the galaxy in its eastern half while a smaller one is visible perpendicular to that along the minor axis. A tidal tail about 1.2 arcminutes long extends to the east-southeast of the galaxy. The halo of the galaxy appears boxy. NGC 3801 has been found to emit radio waves. It is a compact Fanaroff–Riley type I radio galaxy, with the total extent of the jets being 40 arcseconds. Both jets appear to curve while the core is not visible in observations by the Very Large Array. The radio jets have been found to heat the interstellar medium to a temperature of 1 and 0.7 keV. A linear feature is visible in soft X-rays extending along the jet axis, possibly a tidal tail. CO imaging indicates the presence of an edge-on disk with a radius 2 kpc perpendicular to the radio jets axis, with a molecular gas mass of 3×108 M☉, about 1% of the dynamical mass of the galaxy. There is also a clump of molecular gas not associated with the disk that appears to fall towards the galaxy. The radio jet axis is aligned with the main HI disk of the galaxy. When observed in ultraviolet, the galaxy is shaped like an s-shape, with the western half being brighter than the eastern half, indicating the presence of a very warped disk. Both halves extend for 60–70 arcseconds. Small UV clumps appear along the galaxy, that indicate the presence of stars. The age of the stellar population in the clumps is estimated to be between 100 and 500 Myr, with most star forming activity taking place before 400 Myr. The location of the most vigorous starburst appears to be the central region of the galaxy. In the centre of NGC 3801 lies a supermassive black hole whose mass is estimated to be 108.28 ± 0.31 (93 – 390 millions) M☉ based on gas dynamics or 108.43 M☉ based on stellar velocity dispersion. The nucleus of the galaxy has been categorised as in between a Seyfert galaxy and a LINER.

Nearby galaxies NGC 3801 is the foremost galaxy of the galaxy group known as NGC 3801 group or LGG 246. Other members of the group include the galaxies NGC 3768, NGC 3790, NGC 3799, NGC 3800, NGC 3802, NGC 3806, NGC 3827, and NGC 3853. NGC 3802 lies 2.3 arcminutes from NGC 3801 while NGC 3790 lies 7 arcminutes away. HI imaging shows a hydrogen bridge that appears to link NGC 3801 and NGC 3802, indicating the two galaxies are interacting.

Gallery

See also 3C 285 - a similar radio galaxy

References

External links Media related to NGC 3801 at Wikimedia Commons NGC 3801 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images NGC 3801 on SIMBAD

Illustrations

Worked examples

Example 1 — a first encounter with NGC 3801

Start with the simplest possible case. Write down what NGC 3801 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 3801 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 3801 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 3801

In research: NGC 3801 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 3801 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 3801 is common in secondary-school and first-year university syllabi. It links to neighbouring topics 4C objects, Astronomical objects discovered in 1784, Discoveries by William Herschel, so understanding it makes those chapters shorter.
In everyday life: Look for NGC 3801 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 3801 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what NGC 3801 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 3801 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is NGC 3801 in simple terms?

NGC 3801 is a lenticular galaxy located in the constellation Leo. It is about 150 million light years from Earth, and estimated to be about 170,000 light years in diameter.

Why does NGC 3801 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 3801?

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 3801.