science

Lacerta

Lacerta 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 Lacerta rather than just read about it. In short: Lacerta is one of the 88 modern constellations defined by the International Astronomical Union. Its name is Latin for lizard.

Key takeaways

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

Reference excerpt

Lacerta is one of the 88 modern constellations defined by the International Astronomical Union. Its name is Latin for lizard. A small, faint constellation, it was defined in 1687 by the astronomer Johannes Hevelius. Its brightest stars form a "W" shape similar to that of Cassiopeia, and it is thus sometimes referred to as 'Little Cassiopeia'. It is located between Cygnus, Cassiopeia and Andromeda on the northern celestial sphere. The northern part lies on the Milky Way.

Features

Lacerta is typical of Milky Way constellations: no bright galaxies, nor globular clusters, but instead open clusters, for example NGC 7243, the faint planetary nebula IC 5217 and quite a few double stars. It also contains the prototypic blazar BL Lacertae. Lacerta contains no Messier objects.

Stars

Alpha Lacertae is a blue-white hued main-sequence star of magnitude 3.8, 102 light-years from Earth. It has a spectral type of A1 V and is an optical double star. Beta Lacertae is far dimmer, a yellow giant of magnitude 4.4, 170 light-years from Earth. Roe 47 is a multiple star consisting of five components (magnitudes 5.8, 9.8, 10.1, 9.4, 9.8). ADS 16402 is a binary star system in Lacerta, around which a planet orbits with some unusual properties. The Jupiter-sized planet exhibits an unexpectedly low density, about the same as cork. This planet is dubbed HAT P-1. EV Lacertae is a rapidly spinning magnitude 10 red dwarf with a strong magnetic field. It is a flare star that can emit powerful flares potentially visible to the naked eye, thousands of times more energetic than any from Earth's sun. HD 215441 (22h 44m.2 / +55° 35') is known as Babcock's Magnetic Star. Source: Sky Catalogue 2000.0 Volume 2: Double Stars, Variable Stars and Nonstellar Objects, page xlv, chapter Glossary of Selected Astronomical Names.

Deep-sky objects The constellation of Lacerta is best known for Sh 2-126, the Great Lacerta Nebula, which is a massive and faint emission nebula visible in Hydrogen alpha. NGC 7243 is an open cluster 2500 light-years from Earth, visible in small amateur telescopes. It has a few dozen "scattered" stars, the brightest of which are of the 8th magnitude. BL Lacertae is the prototype of the BL Lacertae objects, which appear to be dim variable stars but are actually the variable nuclei of elliptical galaxies; they are similar to quasars. It lent its name to a whole type of celestial objects, the BL Lacertae objects (a subtype of blazar). The object varies irregularly between magnitudes 14 and 17 over a few days.

History

Centred on a region of the sky without apparently bright stars, Lacerta was apparently not regarded as a constellation by ancient Western astronomers. Johannes Hevelius created the constellation in 1687 and initially named it "Stellio" (the stellion), a lizard with star-like dorsal spots found along the Mediterranean coast. Other Europeans who sought to name this new constellation included Augustin Royer, who created Sceptrum et Manus Iustitiae (the Hand of Justice and Sceptre) to honor Louis XIV in 1670, and Johann Elert Bode, who created Frederici Honores (Frederick's Glory) to honor Frederick the Great in 1787. Both Sceptrum and Frederici Honores are now obsolete, while Lacerta still survives.

Equivalents Although not included in ancient star charts of Europe and the Near East, the stars of Lacerta, along with some in the eastern portion of Cygnus, were coincidentally combined by early Chinese astronomers into their "Flying serpent". Similarly, the Chumash people of California call this part of the sky 'Lizard' and include it in multiple stories.

Namesakes USS Lacerta (AKA-29) was an attack cargo ship in the United States navy named after the constellation.

Illustrations

Worked examples

Example 1 — a first encounter with Lacerta

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

In research: Lacerta 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 Lacerta 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: Lacerta is common in secondary-school and first-year university syllabi. It links to neighbouring topics Constellations listed by Johannes Hevelius, Lacerta, Northern constellations, so understanding it makes those chapters shorter.
In everyday life: Look for Lacerta 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 Lacerta in 20 minutes

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

Frequently asked questions

What is Lacerta in simple terms?

Lacerta is one of the 88 modern constellations defined by the International Astronomical Union. Its name is Latin for lizard.

Why does Lacerta 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 Lacerta?

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 Lacerta.