Extremely large main sequence stars consume their fuel quickly and burn hot and bright. As they consume all their hydrogen, they become supergiants. Describe the changes that take place, in terms of luminosity and temperature, to these large main sequence stars as they exhaust their hydrogen supplies.

Identify the correct relation showing that the radius r of the orbit of a moon of a given planet can be determined from the radius r of the planet, the acceleration of gravity at the surface of the planet, and the time τ required by the moon to complete one full revolution about the planet. determine the acceleration of gravity at the surface of the planet jupiter knowing that r = 71 492 km and that t= 3.551 days and r= 670.9 × 10^3 km for its moon europa.