What is Variable: Definition and 1000 Discussions

A variable star is a star whose brightness as seen from Earth (its apparent magnitude) fluctuates.
This variation may be caused by a change in emitted light or by something partly blocking the light, so variable stars are classified as either:

Intrinsic variables, whose luminosity actually changes; for example, because the star periodically swells and shrinks.
Extrinsic variables, whose apparent changes in brightness are due to changes in the amount of their light that can reach Earth; for example, because the star has an orbiting companion that sometimes eclipses it.Many, possibly most, stars have at least some variation in luminosity: the energy output of our Sun, for example, varies by about 0.1% over an 11-year solar cycle.

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  1. M

    Exponential Random Variable

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  2. D

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  3. R

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  4. C

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  6. L

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  7. S

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  8. M

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  9. A

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  10. W

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  11. R

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  12. M

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  13. N

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  14. A

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  15. S

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  16. P

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  17. PsychonautQQ

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  18. G

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  19. BruceW

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  20. M

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  21. D

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  22. F

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  23. X

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  24. J

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  29. Saitama

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  33. M

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  37. M

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  38. O

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  39. E

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  40. Jeffack

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  41. I

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  42. P

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  44. trash

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  46. K

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  49. B

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