Question

Asteroids can be classified into two broad groups based on their composition and location: carbon-rich asteroids dominate the outer part of the asteroid belt, whereas metal-rich asteroids dominate the inner part of the belt. Analysis of the fragment we have discussed in this project reveals that it contains nearly equal amounts of metals and carbon. Can you conclude that the original whole asteroid had a similar composition? Can you conclude with a high degree of confidence that the asteroid originated in the middle regions of the asteroid belt? Explain your reasoning. If you would need more data from the asteroid analysis, what would you like to see?

Answer 1

As an asteroid enters the Earth's atmosphere, the high velocity of the asteroid creates forces of drag with the air. The resulting friction, releases a lot of heat. At high temperatures the constituents of the asteroid react with the gases in the atmosphere and produce oxides and nitrides. These are usually dispersed in the atmosphere as gases. An asteroid that has a larger amount of carbon is more likely to be dispersed in the atmosphere and a smaller fragment reaches the ground.

It is difficult to make any conclusion about the composition of the asteroid from the composition of the fragment that is recovered. As explained earlier, the carbon dioxide produced by the oxidation of the carbon in the asteroid is more likely to be lost compared to the oxides of the other metals that make up the asteroid.

An asteroid fragment with equal amounts of metal and carbon could have been one that was carbon rich before it entered the atmosphere. In that case, it would have been one from the outer part of the asteroid belt. On the other hand, a metal rich asteroid, from the inner part of the belt, could end up as a fragment with an equal composition of metal and carbon.