astronomy

Perdita (moon)

Perdita (moon) 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 Perdita (moon) rather than just read about it. In short: Perdita is a small inner satellite of Uranus. Perdita's discovery was very complicated, as the first photographs of Perdita were taken by the Voyager 2 spacecraft in 1986, but it was not recognized from the photographs for more than a decade.

Key takeaways

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

Reference excerpt

Perdita is a small inner satellite of Uranus. Perdita's discovery was very complicated, as the first photographs of Perdita were taken by the Voyager 2 spacecraft in 1986, but it was not recognized from the photographs for more than a decade. In 1999, the moon was noticed by Erich Karkoschka and reported. However, because no further pictures could be taken to confirm its existence, it was officially demoted in 2001. However, in 2003, pictures taken by the Hubble Space Telescope managed to pick up an object where Perdita was supposed to be, finally confirming its existence. Following its discovery in 1999, it was given the temporary designation of S/1986 U 10. It was named Perdita (Latin for 'lost') after the daughter of Leontes and Hermione in William Shakespeare's play The Winter's Tale. The moon is also designated Uranus XXV.

The moon orbits between Belinda and Puck. The above-mentioned Hubble measurements prove that Perdita does not follow a direct Keplerian motion around Uranus. Instead, it is clearly caught in a 43:44 orbital resonance with the nearby moon Belinda, and from this resonance it has been determined that Belinda's mass is 26 or 27 times that of Perdita. It is also close to an 8:7 resonance with Rosalind. Perdita belongs to the Portia group of satellites, which also includes Bianca, Cressida, Desdemona, Portia, Juliet, Cupid, Rosalind, and Belinda. These satellites have similar orbits and photometric properties. Little is known about Perdita apart from its orbit, radius of 13.3 km (8.3 mi), and geometric albedo of 0.08.

See also Moons of Uranus Natural satellite

Notes

References

Citations

Sources Karkoschka, Erich (2001). "Voyager's Eleventh Discovery of a Satellite of Uranus and Photometry and the First Size Measurements of Nine Satellites". Icarus. 151 (1): 69–77. Bibcode:2001Icar..151...69K. doi:10.1006/icar.2001.6597. Karkoschka, Erich (2001). "Comprehensive Photometry of the Rings and 16 Satellites of Uranus with the Hubble Space Telescope". Icarus. 151 (1): 51–68. Bibcode:2001Icar..151...51K. doi:10.1006/icar.2001.6596. Green, Daniel W. E. (May 18, 1999). "S/1986 U 10". IAU Circular. 7171: 1. Bibcode:1999IAUC.7171....1K. ISSN 0081-0304. Retrieved 2012-01-26. Foust, Jeff (December 31, 2001). "Moon of Uranus is demoted". Spaceflight Now. Retrieved 2012-01-26. Showalter, Mark R.; Lissauer, Jack J. (2006-02-17). "The Second Ring-Moon System of Uranus: Discovery and Dynamics". Science. 311 (5763): 973–977. Bibcode:2006Sci...311..973S. doi:10.1126/science.1122882. PMID 16373533. S2CID 13240973. Green, Daniel W. E. (September 3, 2003). "Satellites of Uranus". IAU Circular. 8194. ISSN 0081-0304. Retrieved 2012-01-26. USGS/IAU (July 21, 2006). "Planet and Satellite Names and Discoverers". Gazetteer of Planetary Nomenclature. USGS Astrogeology. Retrieved 2012-01-26. Ćuk, Matija; French, Robert S.; Showalter, Mark R.; Tiscareno, Matthew S.; Moutamid, Maryame El (2022-07-16). "Cupid is not Doomed Yet: On the Stability of the Inner Moons of Uranus". The Astronomical Journal. 164 (2): 38. arXiv:2205.14272. doi:10.3847/1538-3881/ac745d. ISSN 1538-3881. French, Robert S.; Showalter, Mark R. (August 2012). "Cupid is Doomed: An Analysis of the Stability of the Inner Uranian Satellites". Icarus. 220 (2): 911–921. arXiv:1408.2543. doi:10.1016/j.icarus.2012.06.031.

External links Uranus 'Loses' a Moon: The 'New' Official Moon Count of the Solar System (Archived), Melanie Melton, The Planetary Society, 20 December 2001

Illustrations

Worked examples

Example 1 — a first encounter with Perdita (moon)

Start with the simplest possible case. Write down what Perdita (moon) 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 Perdita (moon) 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 Perdita (moon) 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 Perdita (moon)

In research: Perdita (moon) 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 Perdita (moon) 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: Perdita (moon) is common in secondary-school and first-year university syllabi. It links to neighbouring topics Astronomical objects discovered in 1999, Moons of Uranus, Moons with a prograde orbit, so understanding it makes those chapters shorter.
In everyday life: Look for Perdita (moon) 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 Perdita (moon) in 20 minutes

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

Frequently asked questions

What is Perdita (moon) in simple terms?

Why does Perdita (moon) 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 Perdita (moon)?

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 Perdita (moon).