astronomy

Wolf 922

Wolf 922 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 Wolf 922 rather than just read about it. In short: Wolf 922, also designated Gliese 831, is a nearby binary star composed of two low-mass red dwarfs in the zodiac constellation of Capricornus, close to the border with Aquarius. It has an apparent magnitude that varies between 11.96 and 11.99, far too faint to be seen by the naked eye from Earth but observable using a telescope with an aperture of 51 millimetres (2.0 in) or larger.

Key takeaways

Wolf 922 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Wolf 922 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Wolf 922 from memory before moving on to harder problems.

Reference excerpt

Wolf 922, also designated Gliese 831, is a nearby binary star composed of two low-mass red dwarfs in the zodiac constellation of Capricornus, close to the border with Aquarius. It has an apparent magnitude that varies between 11.96 and 11.99, far too faint to be seen by the naked eye from Earth but observable using a telescope with an aperture of 51 millimetres (2.0 in) or larger. It is located approximately 26 light-years (8.0 pc) distant based on parallax measurements, and approaching the Solar System at a heliocentric radial velocity of −56.33 km/s.

In 1994, it was discovered to show long-term variations in brightness by Edward W. Weis at the Van Vleck Observatory. It was given the variable-star designation BB Capricorni and classified as a BY Draconis variable in 1997.

Observational history As early as 1960, the star was suspected of experiencing perturbations and a period of about 1,500 days (4.1 years) was suggested. It was subsequently examined by Sarah Lee Lippincott, who, in 1979, determined that the perturbing companion star had a mass of between 0.13 and 0.20 M☉, and that it orbited the primary in a moderately eccentric (eccentricity 0.36) 1.93-year orbit. A 1987 paper proposed a circular (eccentricity 0.0) orbit with a period of 1.92 years, but a study in 2016 gives a 704.9-day (1.930-year) period and an eccentricity of 0.39, close to Lippincott's figures. In 1997, the discovery of a third star was tentatively announced, which was described as a likely flare star with a very small mass (0.11 M☉) and luminosity, either located very close to A or B, or farther than about 0.5 arcseconds from the pair. The former possibility was ruled out by a follow-up study in 2000, which stated that if the object exists, it is likely bluer than the two red dwarfs, meaning it could be a white dwarf companion or an unrelated background object.

References

Illustrations

Worked examples

Example 1 — a first encounter with Wolf 922

Start with the simplest possible case. Write down what Wolf 922 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 Wolf 922 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 Wolf 922 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 Wolf 922

In research: Wolf 922 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 Wolf 922 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: Wolf 922 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Binary stars, Capricornus, Gliese and GJ objects, so understanding it makes those chapters shorter.
In everyday life: Look for Wolf 922 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 Wolf 922 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Wolf 922 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 Wolf 922 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Wolf 922 in simple terms?

Why does Wolf 922 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 Wolf 922?

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 Wolf 922.