Red dwarf stars are known for their longevity. The average lifespan of a red dwarf star is estimated to be between 10 trillion and 20 trillion years. This is significantly longer than the lifespan of larger, hotter stars like our Sun, which has a lifespan of about 10 billion years.

The key factor contributing to the long lifespan of red dwarf stars is their low mass and slow rate of fuel consumption. Red dwarf stars have a mass that is only a fraction of the Sun's mass, typically ranging from 0.08 to 0.5 solar masses. Due to their low mass, red dwarf stars have a weaker gravitational force and thus experience a lower rate of hydrogen fusion in their cores. As a result, they burn their fuel at a much slower pace compared to larger stars.

Additionally, red dwarf stars are very energy-efficient. They emit a significant portion of their energy in the infrared spectrum, which means they lose heat more slowly compared to hotter stars. This energy efficiency further contributes to their extended lifespan.

As the universe ages and larger stars exhaust their fuel supply and eventually die, red dwarf stars will continue to shine. In the distant future, they will be the dominant type of star in the universe.