astronomy

NGC 5084

NGC 5084 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 5084 rather than just read about it. In short: NGC 5084 is a Seyfert 2 lenticular galaxy in the constellation of Virgo. It is located at a distance of about 25.1 megaparsecs (81.9 million light-years) from Earth, which, given its apparent dimensions using the 90% total light definition, means that NGC 5084 is 236 kiloparsecs (770,000 light-years) across.

Key takeaways

NGC 5084 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 5084 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of NGC 5084 from memory before moving on to harder problems.

Reference excerpt

NGC 5084 is a Seyfert 2 lenticular galaxy in the constellation of Virgo. It is located at a distance of about 25.1 megaparsecs (81.9 million light-years) from Earth, which, given its apparent dimensions using the 90% total light definition, means that NGC 5084 is 236 kiloparsecs (770,000 light-years) across. It is one of the largest and most massive galaxies in the Virgo Supercluster. William Herschel discovered it on March 10, 1785. It is a member of the NGC 5084 Group of galaxies, which is a member of the Virgo II Groups, a series of galaxies and galaxy clusters strung out from the southern edge of the Virgo Supercluster. The galaxy is seen nearly edge-on, with inclination 86°, and features a warped disk and large quantities of HI gas extending along the disk, probably accumulated after multiple accretions of smaller galaxies. NGC 5084 also possess an active galactic nucleus.

Mass and size estimates NGC 5084 is a very massive system, with a high rotational speed of about 328 km/s. It is categorised as a supermassive disk galaxy. Gottesen (1986) estimated based on the rotational speed that the mass of NGC 5084 is 8.5×1011 M☉ and its radius to be 34 kpc for an estimated distance of 15.5 Mpc. Gottesman et al. (2002) using the same method adopted as distance the 30 Mpc and calculated the mass of NGC 5084 to be 1.7×1012 M☉. Koribalski et al. (2004) measured the rotational speed of NGC 5084 to be 334 km/s and calculated its mass to be 1.3×1012 M☉ and its radius was estimated at 50 kpc. Carrignan et al. (1997) measured the velocity differences and projected separations of nine galaxies they identified as satellites of NGC 5084 and using different equations they estimated the mass of NGC 5084 to be between 6×1012 M☉ and 1×1013 M☉, which was at that time the highest mass ever derived for a disk galaxy. They estimated the optical diameter of NGC 5084 to be 74 kpc. An estimation of NGC 5084's size using the 90% total light definition yields a very substantial apparent diameter of 1,949.84 arcseconds, which corresponds to a diameter of 235.93 kiloparsecs (770,000 light-years) assuming the currently accepted distance to the galaxy. This would make it one of the largest known lenticular and supermassive disk galaxies.

Nearby galaxies NGC 5084 is the largest galaxy in the NGC 5084 group, which also includes NGC 5087 and NGC 5134 and some smaller galaxies. The galaxy group is compact, showing little redshift dispersion. NGC 5068 is a foreground galaxy. Other nearby galaxy groups include the NGC 5078 group, which includes NGC 5078, NGC 5061, and NGC 5101, and NGC 4965 group. NGC 5084 is located at end of Virgo II groups, a filament of galaxy groups that extends southwards from the Virgo Cluster, and is part of the Virgo Supercluster.

See also NGC 1961 - a supermassive spiral galaxy UGC 12591 - a supermassive lenticular/spiral galaxy

Gallery

Notes

References

Further reading Theureau, G.; Hanski, M. O.; Coudreau, N.; Hallet, N.; Martin, J.-M. (19 December 2006). "Kinematics of the Local Universe". Astronomy & Astrophysics. 465 (1): 71–85. arXiv:astro-ph/0611626. Bibcode:2007A&A...465...71T. doi:10.1051/0004-6361:20066187. S2CID 14251529.

External links "NGC5084". HyperLeda. University of Lyon.

NGC 5084 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 5084

Start with the simplest possible case. Write down what NGC 5084 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 5084 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 5084 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 5084

In research: NGC 5084 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 5084 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 5084 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Discoveries by William Herschel, Lenticular galaxies, NGC 5084 Group, so understanding it makes those chapters shorter.
In everyday life: Look for NGC 5084 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 5084 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what NGC 5084 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 5084 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is NGC 5084 in simple terms?

Why does NGC 5084 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 5084?

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 5084.