Stars

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Star Noun

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[star]

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Star

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A huge ball of very hot, glowing gas that gives off both heat and light, held together by its own gravity.

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Example: This image shows the Sun, which is the star at the center of our solar system, with planets orbiting it.

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Binary System Noun

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[by-nair-ee sis-tuhm]

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Binary System

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A system where two stars are gravitationally bound together and orbit a common center of mass.

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Example: This image shows a binary system, where two stars are gravitationally bound and orbit a common center of mass.

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Kelvin Noun

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[kel-vin]

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Kelvin

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The scientific unit of measurement for temperature used to measure a star's surface temperature, where the lowest point is absolute zero.

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Example: This scale shows how light color is measured in Kelvin (K). Hotter objects, like blue stars, have a higher Kelvin temperature than cooler, red stars.

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Luminosity Noun

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[loo-mi-nos-i-tee]

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Luminosity

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The intrinsic brightness of a celestial object, representing the total amount of energy it emits per unit of time.

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Example: A star's luminosity is its total energy output, which radiates outward in all directions, spreading over a larger area as the distance (d) increases.

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Absolute Magnitude Noun

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[ab-suh-loot mag-ni-tood]

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Absolute Magnitude

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A measure of a star's luminosity, representing how bright it would appear if located at a standard, fixed distance.

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Example: This diagram shows that absolute magnitude (M) is a star's brightness measured from a standard distance, unlike apparent magnitude (m) which depends on actual distance.

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Apparent Magnitude Noun

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[uh-pair-uhnt mag-ni-tood]

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Apparent Magnitude

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A measure of how bright a star appears from Earth, which depends on its luminosity, size, and distance from us.

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Example: This scale shows the apparent magnitude of different celestial objects. Brighter objects like the Sun have a lower, negative number, while dimmer objects have a higher number.

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Element Noun

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[el-uh-muhnt]

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Element

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A pure substance that cannot be broken down into simpler substances by chemical means, which forms the composition of stars.

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Example: This diagram shows the structure of an oxygen atom, an example of an element, with its core nucleus (protons, neutrons) and orbiting electrons.

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Mass Noun

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[mas]

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Mass

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The amount of matter in an object, which for a star, helps determine its temperature, brightness, and life cycle.

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Example: This image shows a balance scale, where the side with the apple is lower, indicating it has more mass than the 1-gram weight.

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Solar Radius Noun

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[soh-ler rey-dee-uhs]

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Solar Radius

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A standard unit of distance, equal to the radius of the Sun, used to express the size of other stars.

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Example: This image compares the sizes of different stars, using 'solar radii' as a unit of measurement to show how much larger other stars are than our Sun.

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Spectroscope Noun

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[spek-truh-skohp]

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Spectroscope

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A special scientific tool used to analyze the light emitted from a star to determine its physical properties and composition.

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Example: This diagram shows how a spectroscope reveals that each element, like Hydrogen (H), has a unique 'fingerprint' of light, allowing astronomers to identify elements in stars.