astronomy

Leo II (dwarf galaxy)

Leo II (dwarf galaxy) 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 Leo II (dwarf galaxy) rather than just read about it. In short: Leo II (or Leo B) is a dwarf spheroidal galaxy about 690,000 light-years away in the constellation Leo. It is one of 24 known satellite galaxies of the Milky Way.

Key takeaways

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

Reference excerpt

Leo II (or Leo B) is a dwarf spheroidal galaxy about 690,000 light-years away in the constellation Leo. It is one of 24 known satellite galaxies of the Milky Way. Leo II is thought to have a core radius of 178 ± 13 pc and a tidal radius of 632 ± 32 pc. It was discovered in 1950 by Robert George Harrington and Albert George Wilson, from the Mount Wilson and Palomar Observatories in California. In 2007 a team of 15 scientists observed Leo II through the 8.2 meter Subaru optical-infrared telescope in Mauna Kea, Hawaii. Over 2 nights, 90 minutes of exposures were taken and 82,252 stars were detected down to a visible magnitude of 26. They found that Leo II consists largely of metal-poor older stars, a sign that it has survived the galactic cannibalism under which massive galaxies (e.g., the Milky Way) consume smaller galaxies to attain their extensive size. Observation at ESO estimates Leo II's mass to be (2.7 ± 0.5)×107 M☉.

See also Dwarf galaxy Local Group, a description of the group of galaxies that includes the Milky Way.

References

Harrington R. G.; Wilson A. G. (1950). "Two New Stellar Systems in Leo". Publications of the Astronomical Society of the Pacific. 62 (365): 118–120. Bibcode:1950PASP...62..118H. doi:10.1086/126249.

External links Media related to Leo II (dwarf galaxy) at Wikimedia Commons

Illustrations

Worked examples

Example 1 — a first encounter with Leo II (dwarf galaxy)

Start with the simplest possible case. Write down what Leo II (dwarf galaxy) 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 Leo II (dwarf galaxy) 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 Leo II (dwarf galaxy) 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 Leo II (dwarf galaxy)

In research: Leo II (dwarf galaxy) 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 Leo II (dwarf galaxy) 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: Leo II (dwarf galaxy) is common in secondary-school and first-year university syllabi. It links to neighbouring topics Astronomical objects discovered in 1950, Dwarf elliptical galaxies, Elliptical galaxy stubs, so understanding it makes those chapters shorter.
In everyday life: Look for Leo II (dwarf galaxy) 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 Leo II (dwarf galaxy) in 20 minutes

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

Frequently asked questions

What is Leo II (dwarf galaxy) in simple terms?

Leo II (or Leo B) is a dwarf spheroidal galaxy about 690,000 light-years away in the constellation Leo. It is one of 24 known satellite galaxies of the Milky Way.

Why does Leo II (dwarf galaxy) 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 Leo II (dwarf galaxy)?

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 Leo II (dwarf galaxy).