astronomy

HD 8357

HD 8357 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 HD 8357 rather than just read about it. In short: AR Piscium is a binary star system in the northern constellation of Canes Venatici, abbreviated AR Psc. It has the Henry Draper Catalogue identifier HD 8357; AR Piscium is its variable star designation.

Key takeaways

HD 8357 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect HD 8357 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of HD 8357 from memory before moving on to harder problems.

Reference excerpt

AR Piscium is a binary star system in the northern constellation of Canes Venatici, abbreviated AR Psc. It has the Henry Draper Catalogue identifier HD 8357; AR Piscium is its variable star designation. The pair have a combined apparent visual magnitude that fluctuates around 7.24, which is too faint to be readily visible to the naked eye. Parallax measurements place it at a distance of 148 light years from the Sun. The motion of this star through the Milky Way suggests it is a member of the intermediate disc population. Variable X-ray source H0123+075 was identified from the HEAO 1 A-2 experiment and published by F. E. Marshall and associates in 1979. The following year, M. Garcia and associates identified the most probable source star as HD 8357, and determined it to be a RS Canum Venaticorum variable. This has a spectral class of G5 in the Henry Draper Catalogue. Optical observations by D. S. Hall and associates in 1980–1981 confirmed the source star to be optically variable with a period of 12.3±0.1 d. In 1993, AR Psc was identified as an extreme ultraviolet source by K. A. Pounds and associates using ROSAT. This is a double-lined spectroscopic binary with an orbital period of 14.3 days and an eccentricity of 0.185. The mass ratio of the two components is 1.222±0.008. The primary component is an evolving subgiant star with a stellar classification of Kl IV. It is the chromospherically active member of this system, displaying visual flares. Intense X-ray flares have been detected. The smaller and less massive secondary star is a G-type main-sequence star with a stellar class of G7 V. Based on the significant difference between the orbital and photometric periods, the two stars are in pseudosynchronous rotation.

References

Illustrations

Worked examples

Example 1 — a first encounter with HD 8357

Start with the simplest possible case. Write down what HD 8357 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 HD 8357 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 HD 8357 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 HD 8357

In research: HD 8357 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 HD 8357 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: HD 8357 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Durchmusterung objects, G-type main-sequence stars, Gliese and GJ objects, so understanding it makes those chapters shorter.
In everyday life: Look for HD 8357 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 “HD 8357” →

Affiliate

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

How to study HD 8357 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what HD 8357 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 HD 8357 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is HD 8357 in simple terms?

Why does HD 8357 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 HD 8357?

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 HD 8357.