astronomy

NGC 4442

NGC 4442 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 4442 rather than just read about it. In short: NGC 4442 also known as UGC 7583, is a barred lenticular galaxy, luminous infrared galaxy and active galaxy in the constellation of Virgo. The galaxy is 48 million light years (or 14,720,000 parsecs) away at a spectroscopic redshift z = 0.00117.

Key takeaways

NGC 4442 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 4442 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of NGC 4442 from memory before moving on to harder problems.

Reference excerpt

NGC 4442 also known as UGC 7583, is a barred lenticular galaxy, luminous infrared galaxy and active galaxy in the constellation of Virgo. The galaxy is 48 million light years (or 14,720,000 parsecs) away at a spectroscopic redshift z = 0.00117. The galaxy has a visual magnitude of 10.6, which is visible using a telescope with an aperture of 6 inches or more, and it can be observed in both hemispheres during certain times of the year. The galaxy is located in the Virgo Cluster, along with other notable galaxies such as Messier 87 and the Eyes Galaxies. The galaxy was discovered on April 15, 1784 by German-British astronomer, William Herschel.

Physical properties NGC 4442 is medium-sized barred lenticular galaxy located in the Virgo Cluster, and it was listed as the 1,062nd object in the Virgo Cluster Catalog (VCC). The galaxy has an estimated width of 83,000 light years (or 25,490 parsecs) across, or about 3/4 the size of the Milky Way. This size is based on an 2MASS K-band total angular diameter of 5.95 arcmin (or 357 arcsecs) and a mean redshift-independent distance of 48 million light years (or 14,720,000 parsecs). NGC 4442 has a stellar mass of 162 billion M☉, or 10^11.21. The galaxy is roughly 3/4th the stellar mass of the Milky Way. The galaxy has a large stellar population of red-giant branch stars (also known as RGB stars), with an average age of 3.92 billion years old, and an mean mass of 1.09 M☉. The neutral atomic hydrogen in the galaxy has an mass of 54.9 million M☉, and this gas is usually found in the outer regions of the galaxy such as the galactic halo. NGC 4442 has a K-band luminosity of 550 billion L☉, or 10^11.74 and therefore it is classified as a luminous infrared galaxy (also referred as LIRGs). The galaxy is one of the closest luminous infrared galaxies known, with a similar distance to other nearby luminous infrared galaxies such as Messier 77. NGC 4442 has a star-formation rate of 10.7 M☉ per year, extremely high for gas-poor lenticular galaxies. Despite its high-star formation rate it is not classified as a starburst galaxy, and the galaxy's star-formation rate is comparable to other lenticular galaxies such as Messier 85. The total mass of the ionized atomic hydrogen in the galaxy, which mostly includes the star-forming regions is 109.6 million M☉, or 10^8.04. The galactic center of NGC 4442 shows a clear active galactic nucleus (also called AGNs), which is a region at the center of a galaxy that is extremely luminous and bright. The active galactic nucleus is powered by a massive supermassive black hole (also known as SMBHs) with a mass of 5.25 billion M☉ or roughly 1,200 times more massive than Sagittarius A*, which is the central black hole of the Milky Way. NGC 4442 has a population of 219 globular clusters, however some of them are potentially not globular clusters and are candidates. The globular clusters have angular radii between 0.0103 and 0.1042 arcsecs, corresponding to a half-light radius ranging from 2.41 to 24.3 light years (or 0.74 to 7.44 parsecs).

Supernova One supernova has been identified in NGC 4442: SN 2021qvv, which had a peak magnitude of 13.8 in July 2021, and it was classified as a Type Ia supernova (abbreviated as SNIa). SN 2021qvv was discovered on June 24, 2021, by the Las Cumbres Observatory. The supernova had a maximum absolute luminosity of -16.42, equivalent to 316 million L☉ and was considered a underluminous supernova similar to other supernovae such as SN 2006mr. The supernova was formed by the collision of two white dwarfs with predicted masses of 0.85 M☉ and 1.1 M☉, creating a super-Chandrasekhar white dwarf which collapsed and exploded.

See also Messier 85, a lenticular galaxy that has a similar star-formation rate. Messier 77, another nearby luminous infrared galaxy. NGC 1277, another lenticular galaxy hosting a similar mass central black hole. NGC 1316, host of the underluminous supernova, SN 2006mr.

References

External links

NGC 4442 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 4442

Start with the simplest possible case. Write down what NGC 4442 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 4442 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 4442 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 4442

In research: NGC 4442 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 4442 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 4442 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Active galaxies, Astronomical objects discovered in 1784, Barred lenticular galaxies, so understanding it makes those chapters shorter.
In everyday life: Look for NGC 4442 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 4442 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what NGC 4442 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 4442 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is NGC 4442 in simple terms?

Why does NGC 4442 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 4442?

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 4442.