Final answer:
High-mass stars can burn helium more easily than low-mass stars because their greater mass results in higher core temperatures and pressures, which are crucial for initiating and sustaining helium fusion into heavier elements.
Step-by-step explanation:
High-mass stars can burn helium more readily than low-mass stars because of the extreme pressures and temperatures in their cores. The core temperature of a star, which is essential for the fusion of elements, depends significantly on the star's mass. High-mass stars, due to the significant weight of their overlying layers, reach higher core pressures and temperatures compared to low-mass stars. Consequently, the burning of helium into heavier elements like carbon requires these high temperatures, making high-mass stars adept at this process.
During the main sequence, high-mass stars are characterized by high temperatures and luminosities. Their enormous energy consumption rates lead to rapid exhaustion of hydrogen, which is fused into helium. As the helium accumulates, the conditions set the stage for helium fusion to begin—something that low-mass stars struggle to achieve because they cannot generate the requisite core temperatures for this next phase of fusion.
Thus, high-mass stars have shorter lifespans despite having more fuel, and their ability to burn helium is a direct consequence of their mass and the elevated temperatures and pressures that ensue within their cores.