That could be a comet, or any one of the billions of meteoroids
moving in a cloud that's actually the remains of a shattered comet.
Answer:

Explanation:
Given:
mass of ice melted, 
time taken by the ice to melt, 
latent heat of the ice, 
Now the heat rejected by the Carnot engine:



Since we have boiling water as hot reservoir so:

The cold reservoir is ice, so:

Now the efficiency:



Now form the law of energy conservation:
Heat supplied:

where:
heat supplied to the engine




Now the work done:


