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20 Cards in this Set
- Front
- Back
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what is a star |
celestial body made of hot gases, mainly hydrogen and helium |
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Properties of stars |
Brightness, color, temperature, composition, mass and size |
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Light is a form of _____ that humans can detect |
Energy |
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Light is a form of _____ transmitted by |
Radiation Electromagnetic waves |
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Electromagnetic spectrum |
Arrangement of electromagnetic radiation in differrnt types, each with different ranges of wavelengths |
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What two factors affect how bright a light emitting object appears |
Size abd distance |
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Whats luminosity |
Property of the stars: measure of total amount of energy a star radiates per second (joules/second) |
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How do astronomers infer the temperature of stars |
Color |
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Temperature of red, yellow, blue stars |
Red: cool, 3000°c Yellow: hot, 6000°c Blue: 20 000- 35 000°c |
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What device is used to measure a stars compostion. How is it used |
Spectroscope. Shows different colors and dark bands. Reveals that some wavelengths of light disappeared, absorbed by gases in stars atmosphere. Each element leaves unique pattern of dark bands |
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How do astronauts calculate the size of a star |
Luminosity and temperature |
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Ranges of star sizes |
Dwarf stars, radius of sun 0.10, enourmous stars (1000*size of suns radius) |
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Solar mass of Sun vs other stars |
1 solar mass. Ranges from 0.08-100+ |
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Whats the Hertzsprung Russel Diagram |
Plots the luminosity (y) and color (x) of several thousand stars. Related to mass |
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Upperleft- lower right is |
main sequence containing 90% of known stars |
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Sun is where on HR diagram |
Near middle |
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Cool and bright stars are where in HR diagram |
Above main sequencr. Red giants/suoer giants. |
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Very hot, but dim stars on HR Diagram is where |
Lower left corner. White dwarfs |
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whats absolute magnitude |
magnitude of a star that we would observe if the star were placed 32.6ly from earth |
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define spectral lines |
certain specific wavelengths within a spectrum characterized by lines; identify specific chemical elements |
