We do not expect Mercury to have an atmosphere at all because:
A) it is small.
B) it has a high temperature.
C) it is bombarded by intense solar radiation.
D) all of the above

Question

Quizplus · Accepted Answer

All three reasons contribute to why Mercury would not have an atmosphere. Its small size means that the planet's gravity is not strong enough to hold on to a significant amount of gases. Its high temperature (up to 800 degrees Fahrenheit) would cause any gases to escape, and it is bombarded by intense solar radiation from the sun which would strip away any existing atmosphere overtime.

We Do Not Expect Mercury to Have an Atmosphere at All