Why is the share of bright comets higher among comets with parabolic or even hyperbolic orbits, and among short-period comets

Why is the share of bright comets higher among comets with parabolic or even hyperbolic orbits, and among short-period comets (with a period of less than 100 years) there are very few bright comets?

With each approach to the Sun, the comet loses some of its substance. Short-period comets gradually lose their brightness.

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