astronomy

NGC 7674

NGC 7674 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 7674 rather than just read about it. In short: NGC 7674 is a spiral galaxy located in the constellation Pegasus. It is located at a distance of about 350 million light years from Earth, which, given its apparent dimensions, means that NGC 7674 is about 125,000 light years across.

Key takeaways

NGC 7674 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 7674 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of NGC 7674 from memory before moving on to harder problems.

Reference excerpt

NGC 7674 is a spiral galaxy located in the constellation Pegasus. It is located at a distance of about 350 million light years from Earth, which, given its apparent dimensions, means that NGC 7674 is about 125,000 light years across. It was discovered by British astronomer John Herschel on 16 August 1830.

Characteristics The galaxy is seen nearly face-on, at an inclination of 31 degrees. The central bar-shaped structure, measuring 15×5 arcseconds is made up of stars. The galaxy has two spiral arms that become broader as the distance increases. One arm vanishes at the point it overlaps with the nearby galaxy NGC 7674A. The shape of NGC 7674, including the long narrow streamers emanating northeast and northwest of the galaxy can be accounted for by tidal interactions with its companions. There is no dwarf galaxy seen inside the streamers. It is featured in Arp's Atlas of Peculiar Galaxies as number 182, in the category "galaxies with narrow filaments". NGC 7674 has a powerful active nucleus of the kind known as a type 2 Seyfert that is perhaps fed by gas drawn into the center through the interactions with the companions. In 1975, observations of excess ultraviolet emission led to designation as Markarian 533 in Markarian's catalog. Later, using spectropolarimetry, emission characteristic of a hidden broad-line region (BLR), visible only in the polarized flux spectrum was detected, implying that the nucleus of NGC 7674 is an obscured type 1 Seyfert, hidden by a dust torus. In the center of NGC 7674 lies a supermassive black hole whose mass is estimated to be nearly 3.63×107 M☉ based on stellar velocity dispersion. When observed in radio waves, NGC 7674 features two radio jets with an S-shape, 0.7 kpc long. The reason for this shape may be a change in the black hole spin axis due to a minor merger, the presence of a binary black hole or due to interactions with the interstellar medium. Two radio sources with characteristics similar to accreting supermassive black holes have been observed in the centre of NGC 7674, at a projected separation of 0.35 parsec. NGC 7674 falls into the family of luminous infrared galaxies, with its infrared luminosity being 1011.54 L☉. The luminous infrared galaxies are characterised by intense star forming activity. The total star formation rate in NGC 7674 is estimated to be 54 M☉ per year, and the star formation rate at the nucleus is 4.3 M☉ per year.

Supernovae Two supernovae have been observed in NGC 7674:

SN 2011ee (Type Ic, mag 18.6) was discovered by the European Southern Observatory's Infrared Supernova Search on 27 June 2011. SN 2011hb (Type Ia, mag 18.8) was discovered by the Catalina Real-time Transient Survey and Stan Howerton on 24 October 2011.

Nearby galaxies NGC 7674 is the brightest and largest member of the isolated Hickson 96 compact group of galaxies, consisting of four galaxies. NGC 7674 forms a pair with its smaller companion NGC 7674A, which lies 34 arcseconds to the north. NGC 7675, an elliptical galaxy, lies 2.2 arcminutes to the east.

References

This article incorporates text available under the CC BY 3.0 license.

External links

NGC 7674 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images NGC 7674 on SIMBAD

Illustrations

Worked examples

Example 1 — a first encounter with NGC 7674

Start with the simplest possible case. Write down what NGC 7674 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 7674 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 7674 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 7674

In research: NGC 7674 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 7674 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 7674 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Arp objects, Astronomical objects discovered in 1830, Discoveries by John Herschel, so understanding it makes those chapters shorter.
In everyday life: Look for NGC 7674 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.

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study NGC 7674 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what NGC 7674 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 7674 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is NGC 7674 in simple terms?

Why does NGC 7674 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 7674?

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 7674.