Units of Measurement
Although stellar parameters can be expressed in SI units or CGS units, it is often most convenient to express mass, luminosity, and radii in solar units, based on the characteristics of the Sun:
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solar mass: M⊙ = 1.9891 × 1030 kg solar luminosity: L⊙ = 3.827 × 1026 watts solar radius R⊙ = 6.960 × 108 m
Large lengths, such as the radius of a giant star or the semi-major axis of a binary star system, are often expressed in terms of the astronomical unit (AU)—approximately the mean distance between the Earth and the Sun (150 million km or 93 million miles).
Read more about this topic: Star
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