astronomy

IC 1481

IC 1481 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 IC 1481 rather than just read about it. In short: IC 1481 is a spiral galaxy located in the Pisces constellation. It is located 289 million light years from Earth and was discovered by Austrian astronomer, Rudolf Spitaler on October 6, 1891.

Key takeaways

IC 1481 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect IC 1481 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of IC 1481 from memory before moving on to harder problems.

Reference excerpt

IC 1481 is a spiral galaxy located in the Pisces constellation. It is located 289 million light years from Earth and was discovered by Austrian astronomer, Rudolf Spitaler on October 6, 1891. The galaxy has an approximate diameter of 65,000 light years with a surface brightness of 12.8 square arcmin. According to an optical image, IC 1481 has an Sb morphological classification. The galaxy also contains an active galactic nucleus (AGN). It is classified as a LINER galaxy. showing an extensive narrow-line region. The region of IC 1481 has bright portions forming in a figure eight pattern and extends at Position Angle (PA) = 50° by ~ 13 arcseconds on both sides of its nucleus. It also show emission knots towards the field edges. The stellar population of IC 1481 shows a post-starburst signature, which the Balmer lines contain strong absorption. A luminous H2O maser emission is found towards IC 1481. The spectrum of the maser has a narrow and strong feature of 0.15 Jy and FWHM = 2 km s−1. It is also weak and broad. With an isotropic luminosity of L = 320 LΘ, this suggests a megamaser. The maser features are found distributed, which they contain a velocity gradient. This suggests the AGN of IC 1481 has an unstable molecular gas disk with a mass of (4.3 ± 0.3) × 107 MΘ. The disk is seen edge-on. It has a thickness of 2H = 1.5-4.2 pc and a radius of r = 2.8-14.0 pc making the largest amongst other maser disks observed in other AGNs. Not to mention, the disk has a rotation of Vrot = 124–168 km s−1 and a velocity dispersion measured by △V ≈ 31 km s−1. Further observations found the disk of IC 1481 is huge indicated by its rotation curve being a sub-Keplerian. When compared to the galaxy's black hole mass of <107 MΘ, its mass is higher. One supernova has been observed in IC 1481: SN 2000ey (type Ia, mag. 16.2).

References

Illustrations

Worked examples

Example 1 — a first encounter with IC 1481

Start with the simplest possible case. Write down what IC 1481 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 IC 1481 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 IC 1481 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 IC 1481

In research: IC 1481 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 IC 1481 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: IC 1481 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Active galaxies, Astronomical objects discovered in 1891, Discoveries by Rudolf Ferdinand Spitaler, so understanding it makes those chapters shorter.
In everyday life: Look for IC 1481 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 IC 1481 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what IC 1481 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 IC 1481 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is IC 1481 in simple terms?

IC 1481 is a spiral galaxy located in the Pisces constellation. It is located 289 million light years from Earth and was discovered by Austrian astronomer, Rudolf Spitaler on October 6, 1891.

Why does IC 1481 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 IC 1481?

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 IC 1481.