astronomy

WR 93b

WR 93b 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 WR 93b rather than just read about it. In short: WR 93b is a Wolf-Rayet star in the constellation Scorpius, an extremely rare star on the WO oxygen sequence. It appears near NGC 6357 in the tail of the scorpion.

Key takeaways

WR 93b belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect WR 93b to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of WR 93b from memory before moving on to harder problems.

Reference excerpt

WR 93b is a Wolf-Rayet star in the constellation Scorpius, an extremely rare star on the WO oxygen sequence. It appears near NGC 6357 in the tail of the scorpion.

Discovery WR 93b was discovered in 2003 during a study of emission line stars from the AAO/UKST Southern Galactic Plane Hα Survey. It was published as the fourth galactic WO class star in 1994. This was too late to be included in the VIIth Wolf Rayet catalogue, but it is listed in an annex published in 2006. It lies in the direction of the Galactic Center and is thought to be part of the Scutum-Crux spiral arm. It is highly reddened and interstellar extinction causes it to be 6.5 magnitudes fainter at visual wavelengths than it otherwise would be.

Features WR 93b, of spectral classification WO3, is one of the very few known oxygen-sequence Wolf-Rayet stars, just four in the Milky Way galaxy and six in external galaxies. Modelling the atmosphere gives a luminosity around 110,000 L☉, very low for a Wolf-Rayet star. It is a very small dense star, with a radius less than half of the sun's but with a mass nearly 10 solar masses (M☉). Very strong stellar winds, with a terminal velocity of 5,000 kilometers per second are causing WR 93b to lose 10−5 M☉/year. For comparison, the Sun loses (2–3)×10−14 M☉ per year due to its solar wind, several hundred million times less than WR 93b.

Evolutionary status WO Wolf-Rayet stars are the last evolutionary stage of the most massive stars before exploding as supernovae, possibly with a gamma-ray burst. It is very likely that WR 93b is on its last stages of nuclear fusion, near or beyond the end of helium burning. It has been calculated that WR 93b will explode as a supernova within 8,000 years.

See also WR 102 WR 142 WR 30a List of supernova candidates

References

Illustrations

Worked examples

Example 1 — a first encounter with WR 93b

Start with the simplest possible case. Write down what WR 93b 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 WR 93b 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 WR 93b 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 WR 93b

In research: WR 93b 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 WR 93b 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: WR 93b is common in secondary-school and first-year university syllabi. It links to neighbouring topics Scorpius, Wolf–Rayet stars, so understanding it makes those chapters shorter.
In everyday life: Look for WR 93b 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 WR 93b in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what WR 93b 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 WR 93b out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is WR 93b in simple terms?

WR 93b is a Wolf-Rayet star in the constellation Scorpius, an extremely rare star on the WO oxygen sequence. It appears near NGC 6357 in the tail of the scorpion.

Why does WR 93b 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 WR 93b?

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 WR 93b.