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. K

    MHB Help solving a linear equation in one variable

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  2. E

    Euler - Lagrange Equation(changing variable)

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  3. F

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  4. J

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  5. H

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  6. maistral

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  9. S

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  10. P

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  11. J

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  12. R

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  13. Y

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  14. A

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  15. C

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  16. Jameson

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  17. Jameson

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  18. A

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  19. G

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  20. S

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  23. J

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  24. F

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  25. C

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  30. C

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  31. A

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  32. L

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  33. Petrus

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  35. B

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  37. M

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  38. C

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  39. V

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  40. G

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  41. D

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  42. A

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  43. J

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  44. G

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  45. J

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  46. Y

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  47. A

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  48. twoski

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  49. T

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  50. N

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