Variable Definition and 1000 Threads

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. P

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  2. roms05

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  3. diracdelta

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  4. thankz

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  5. A

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  6. B

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  7. MexChemE

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  8. C

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  9. B

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  10. CAH

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  11. CAH

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  12. shanepitts

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  13. J

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  14. L

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  15. S

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  16. J

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  17. jdawg

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  18. T

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  19. W

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  20. D

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  21. A

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  22. C

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  23. T

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  24. E

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  25. END

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  26. perplexabot

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  27. rayne1

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  28. J

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  29. A

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  30. R

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  31. S

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  32. A

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  33. Math Amateur

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  34. E

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  35. J

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  36. Somefantastik

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  37. Jameson

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  38. thegreengineer

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  39. L

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  40. TrickyDicky

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  41. S

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  42. P

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  43. A

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  44. Mr Davis 97

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  45. S

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  46. M

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  47. rajeshputta

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  48. ELB27

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  49. C

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  50. topsquark

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