How does the fuel consumption rate of massive O-type stars compare to that of low-luminosity M-dwarfs?
O-types consume hydrogen rapidly, sometimes in less than a million years.
The difference in lifespan and fuel efficiency between the most massive stars (O-types) and the least massive stars (M-dwarfs) is astronomical, driven by their mass and resulting core conditions. O-type stars are extremely massive and luminous; they burn through their available hydrogen fuel at an incredibly accelerated rate, similar to a paper fire, meaning their main-sequence life is cut short to mere millions of years. In stark contrast, Red Dwarfs operate with extreme thrift. Due to their low mass and the internal churning provided by convection, they can utilize nearly all their hydrogen, extending their main-sequence stability to estimates reaching 14 trillion years—a lifespan far exceeding the current age of the universe.
