In November 2013 an object orbiting the sun seemed to disappear behind the sun. When a satellite did not detect the object, astronomers thought that the object had been destroyed when it passed close to the sun. However, when another satellite detected a small, bright object with a fan shaped tail, astronomers proposed that the object was not destroyed. What type of object were astronomers most likely observing?

Based on the given information, astronomers were most likely observing a comet.

Comets are objects that orbit the sun and are composed of ice, dust, and rocks. When a comet gets close to the sun, the heat causes the ice to vaporize, creating a glowing coma (a cloud of gas and dust) around the central solid core called the nucleus. The solar wind also blows some of the gas and dust away from the nucleus, forming a tail that often appears fan-shaped.

In this case, the object seemed to disappear behind the sun, suggesting that it was passing close to it. When the object was detected again, it displayed the characteristics of a small, bright object with a fan-shaped tail. These observations are consistent with the behavior of comets when they approach the sun, which is why astronomers proposed that the object was a comet that had not been destroyed but instead transformed and became visible again.