astronomy

R136

R136 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 R136 rather than just read about it. In short: R136 (formerly known as RMC 136 from the Radcliffe Observatory Magellanic Clouds catalogue) is the central concentration of stars in the NGC 2070 star cluster, which lies at the centre of the Tarantula Nebula in the Large Magellanic Cloud. When originally named it was an unresolved stellar object (catalogued as HD 38268 and Wolf–Rayet star Brey 82) but is now known to include 72 class O and Wolf–Rayet stars within 5…

Key takeaways

R136 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect R136 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of R136 from memory before moving on to harder problems.

Reference excerpt

R136 (formerly known as RMC 136 from the Radcliffe Observatory Magellanic Clouds catalogue) is the central concentration of stars in the NGC 2070 star cluster, which lies at the centre of the Tarantula Nebula in the Large Magellanic Cloud. When originally named it was an unresolved stellar object (catalogued as HD 38268 and Wolf–Rayet star Brey 82) but is now known to include 72 class O and Wolf–Rayet stars within 5 parsecs (20 arc seconds) of the centre of the cluster. The extreme number and concentration of young massive stars in this part of the LMC qualifies it as a starburst region.

Properties R136 produces most of the energy that makes the Tarantula Nebula visible. The estimated mass of the cluster is 450,000 solar masses, suggesting it may become a globular cluster in the future. R136 has around 200 times the stellar density of a typical OB association such as Cygnus OB2. The central R136 concentration of the cluster is about 2 parsecs across, although the whole NGC 2070 cluster is much larger. R136 is thought to be less than 2 million years old. None of the member stars are significantly evolved, and none are thought to have exploded as supernova. Because of this, the cluster contains no red supergiants, blue hypergiants, or luminous blue variables. The brightest stars are WNh, O supergiants, and OIf/WN slash stars, all extremely massive fully convective stars. A small number of B-type main sequence stars have been detected in the outskirts of the cluster, but less massive and less luminous stars cannot be resolved from the dense cluster core at the large distance of the LMC.

R136a R136a is the bright knot at the centre of R136. It consists of eight extremely massive stars, three of them Wolf–Rayet stars and the rest early O-class stars.

Components The cluster contains many of the most massive and luminous stars known, including R136a1. Within the central 5 parsecs there are 32 of the hottest type O stars (O2.0–3.5), 40 other O stars, and 12 Wolf–Rayet stars, mostly of the extremely luminous WNh type. Within 150 parsecs there are a further 325 O stars and 19 Wolf–Rayet stars. Several runaway stars have been associated with R136, including VFTS 682. R136 was first resolved into three components R136a, R136b, and R136c. R136a was resolved using speckle interferometry and eventually space-based observations into as many as 24 components, dominated by R136a1, R136a2, and R136a3, all three being extremely massive WNh stars several million times more luminous than the sun.

Gallery

Illustrations

Worked examples

Example 1 — a first encounter with R136

Start with the simplest possible case. Write down what R136 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 R136 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 R136 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 R136

In research: R136 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 R136 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: R136 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Astronomical objects discovered in 1920, Dorado, Durchmusterung objects, so understanding it makes those chapters shorter.
In everyday life: Look for R136 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 R136 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what R136 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 R136 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is R136 in simple terms?

Why does R136 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 R136?

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 R136.