science

Massalia family

Massalia family is a science 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 Massalia family rather than just read about it. In short: The Massalia family (adj. Massalian; FIN: 404) is a family of asteroids in the inner asteroid belt, named after its parent body, 20 Massalia.

Key takeaways

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

Reference excerpt

The Massalia family (adj. Massalian; FIN: 404) is a family of asteroids in the inner asteroid belt, named after its parent body, 20 Massalia. It consists of S-type asteroids with very low inclinations, straddling the 1:2 resonances with Mars. There are more than 6,000 known Massalian asteroids.

Characteristics

This is a definite cratering family consisting of 20 Massalia and a mass of small fragments excavated from Massalia's surface by an impact. Massalia is by far the largest member with a diameter of about 150 km, while the next largest body, (7760) 1990 RW3 is only about 7 km in diameter. The mass of all the small members is negligible, less than about 1%, compared to Massalia. The family is fairly young, estimated to have been created by an impact 100 to 200 million years ago. It has a distinctly two-lobed appearance in proper a--e space, with one lobe centered at semi-major axes of 2.38 AU, the other at about 2.43 AU, with the parent body Massalia itself located in between. The bodies in the lobes tend to be smaller on average than those in the central region. It has been shown that this structure is likely caused by slow drift of the semi-major axis caused by the Yarkovsky and YORP effects. Details of the lobes were used to calculate the age of the family. A strong 1:2 orbital resonance with Mars crosses the family at 2.42 AU, and appears responsible for some "leakage" of family members away from the area into higher inclination orbits. The Massalia family or a recent minor collision within it may be the source for the prominent α dust band, the other candidate being a recent collision within the Themis family.

Location and size The Massalian asteroids are located at very low inclinations, straddling the 1:2 resonances with Mars. A HCM numerical analysis by Zappalà in 1995, determined a group of core family members, whose proper orbital elements lie in the approximate ranges

* The Zappalà core members only reach e=0.170 but inspection of more modern proper elements reveals that the family extends at least to e=0.175 At the present epoch, the range of osculating orbital elements of these core members is

The analysis by Zappalà found 42 core members in 1995, while a HCM-analysis by Nesvorný in 2014 yielded 6,424 member asteroids based on the proper elements of a catalog of 398,000 bodies.

List

Interlopers A number of Interlopers have been identified, which share the same orbital elements as the true family members, but cannot have come from the same cratering event because of spectral (hence, compositional) differences. 2946 Muchachos and some other bodies were noted as interlopers during a detailed study of the family, while 2316 Jo-Ann is seen to have the wrong spectrum by inspection of the PDS asteroid taxonomy data set[link removed]. Muchachos is larger than any of the true family members apart from Massalia itself.

References

Worked examples

Example 1 — a first encounter with Massalia family

Start with the simplest possible case. Write down what Massalia family claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, 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 Massalia family 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 Massalia family 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 Massalia family

In research: Massalia family appears in science 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 Massalia family 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: Massalia family is common in secondary-school and first-year university syllabi. It links to neighbouring topics Asteroid groups and families, Massalia asteroids, so understanding it makes those chapters shorter.
In everyday life: Look for Massalia family 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 Massalia family in 20 minutes

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

Frequently asked questions

What is Massalia family in simple terms?

The Massalia family (adj. Massalian; FIN: 404) is a family of asteroids in the inner asteroid belt, named after its parent body, 20 Massalia.

Why does Massalia family matter?

Because it connects several science 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 Massalia family?

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 Massalia family.