astronomy

OI 287

OI 287 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 OI 287 rather than just read about it. In short: OI 287 is a quasar located in the constellation of Gemini. The redshift of the object is (z) 0.444 and it was first discovered as a highly polarized object by astronomers in January 1981, but it also has been classified as a blazar in a 1982 study.

Key takeaways

OI 287 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect OI 287 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of OI 287 from memory before moving on to harder problems.

Reference excerpt

OI 287 is a quasar located in the constellation of Gemini. The redshift of the object is (z) 0.444 and it was first discovered as a highly polarized object by astronomers in January 1981, but it also has been classified as a blazar in a 1982 study.

Description The source of OI 287 has a double-lobed structure based on Very Large Array (VLA) observations made in 1984, however at that time it was unresolved. Radio maps made at 20 and 6 centimeters (cm), would reveal the source has a twin-jet structure, depicted as oscillating. The radio spectrum of the source also has a steep appearance between frequencies of 0.36 and 5 GHz. There is a radio core present with an inverted spectrum between 1.4 and 5 GHz but no variability of its flux density. The core is lowly polarized with polarization levels of only 0.25%. The host galaxy of OI 287 has a circular appearance with an M-R apparent magnitude of -23.0 based on optical imaging. However a study published in 1998, suggested it has a disk morphology when observed through near-infrared imaging, displaying the presence of radio emission. The host is also described as slightly elongated towards its companion located 4.9 kiloparsecs away from it. The optical spectrum of OI 287 shows the presence of rich emission lines featuring both narrow and broad Balmer components, as well as detections of doubly ionized oxygen [O III] emission. The optical continuum of the spectrum is found to be increasing sharply towards the near-infrared, but gets flatter at around 10 microns. A broad-line region was located inside the quasar, described as having an obscured appearance, with its accretion disk also likely obscured as well. The mass range of the torus is 105–107 M☉ and the total thickness of the narrow-line region is approximately 2 × 10−8 parsecs. The supermassive black hole located in the center of OI 287 has an estimated mass of 1.46+1.89−0.82 × 109 M☉.

References

External links OI 287 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images OI 287 on SIMBAD OI 287 on HyperLeda (PGC = 3506791)

Illustrations

Worked examples

Example 1 — a first encounter with OI 287

Start with the simplest possible case. Write down what OI 287 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 OI 287 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 OI 287 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 OI 287

In research: OI 287 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 OI 287 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: OI 287 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Active galaxies, Astronomical objects discovered in 1981, Blazars, so understanding it makes those chapters shorter.
In everyday life: Look for OI 287 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.

Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “OI 287” →

Affiliate

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

How to study OI 287 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what OI 287 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 OI 287 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is OI 287 in simple terms?

Why does OI 287 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 OI 287?

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 OI 287.