astronomy

NGC 4772

NGC 4772 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 4772 rather than just read about it. In short: NGC 4772 is a spiral galaxy in the constellation Virgo. The galaxy lies about 90 million light years away from Earth based on redshift-independent methods, which means, given its apparent dimensions, that NGC 4772 is approximately 85,000 light years across.

Key takeaways

NGC 4772 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 4772 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of NGC 4772 from memory before moving on to harder problems.

Reference excerpt

NGC 4772 is a spiral galaxy in the constellation Virgo. The galaxy lies about 90 million light years away from Earth based on redshift-independent methods, which means, given its apparent dimensions, that NGC 4772 is approximately 85,000 light years across. Based on redshift the galaxy lies at a distance of 13.3 Mpc (43.4 Mly). It was discovered by William Herschel on January 24, 1784.

Characteristics NGC 4772 has a bright circular galactic bulge. The galaxy has a long and broad low-surface-brightness bar in the bulge. The kinematics of the central region indicate the presence of a misaligned bar or disk. However it could also indicate the presence of counter-rotating gas, with the galaxy being at the late stages of a minor merger. The central region of the galaxy is depleted in hydrogen and also has low carbon monoxide emission. The nucleus of the galaxy has been found to be active and based on its spectrum it has been characterised as a type 1.9 LINER. The galaxy has two faint, narrow arms which wrap around the galaxy and form a ring. An outer ring is visible, but appears segmented on its northern and southern part. A dust lane surrounds the bulge. The dust lane has some filaments which resemble a spiral structure. The dust lane region also features H-alpha and hydrogen line emission. The hydrogen emission is distributed in two rings around the nucleus. The inner ring has a radius of 60 arcseconds and the outer ring a radius of 200 arcseconds. There is a faint blue stellar location at the outer ring, while the inner ring coincides with active star formation regions. The two rings have slightly different position angles. Carbon monoxide emission is asymmetric and is distributed along the inner hydrogen ring. The star formation rate of the galaxy is about 0.03 M☉ per year.

Supernovae Two supernovae have been observed in NGC 4772:

SN 1988E was discovered on 20 January 1988 by Yoshiaki Taniguchi at an apparent magnitude of 17. It was initially identified as a Type II supernova well past maximum, but further observations found it was depleted in hydrogen and was thus reclassified as a Type I supernova about 300 days post maximum light. SN 2012cu was discovered on 14 June 2012 by Koichi Itagaki at an apparent magnitude of 16.3. Its spectrum revealed it was a Type Ia supernova near maximum light. The supernova was highly reddened due to extinction by dust.

Nearby galaxies NGC 4772 is a member of the NGC 4753 Group, along with NGC 4629, NGC 4691, NGC 4753, NGC 4771, NGC 4845, and NGC 4904. It is part of a Virgo II Groups, a chain of groups extending from the Virgo Cluster. NGC 4772 lies near the outer regions of the Virgo Cluster and has been considered an outlying member of it. The high-surface brightness galaxy CGCG 015-036 lies 18.5 arcminutes away, while the galaxy pair of NGC 4809 and NGC 4810 lies 35 arcminutes to the northeast and at a similar redshift.

Gallery

References

External links

NGC 4772 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images NGC 4772 on SIMBAD

Illustrations

Worked examples

Example 1 — a first encounter with NGC 4772

Start with the simplest possible case. Write down what NGC 4772 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 4772 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 4772 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 4772

In research: NGC 4772 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 4772 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 4772 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Astronomical objects discovered in 1784, Discoveries by William Herschel, LINER galaxies, so understanding it makes those chapters shorter.
In everyday life: Look for NGC 4772 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 4772 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what NGC 4772 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 4772 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is NGC 4772 in simple terms?

Why does NGC 4772 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 4772?

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 4772.