You're likely referring to the corona, which is the outermost layer of the Sun's atmosphere. It's not actually a circle, but rather a vast, faint, and extremely hot region that extends far beyond the visible surface of the Sun (photosphere).

Here's a breakdown of the "circle around the majestic sun":

* Appearance: The corona is only visible during a total solar eclipse, when the Moon blocks out the Sun's bright light. It appears as a faint, white halo around the eclipsed Sun.

* Composition: The corona is made up of extremely hot, low-density plasma, primarily consisting of ionized hydrogen and helium.

* Temperature: Surprisingly, the corona is incredibly hot, reaching millions of degrees Celsius, while the surface of the Sun (photosphere) is only about 5,500 degrees Celsius.

* Origin of Temperature: The exact mechanism behind the corona's extreme temperature is still not fully understood. Scientists suspect that it might be caused by magnetic waves or nanoflares, small explosions on the Sun's surface.

So, while not technically a "circle", the corona is a stunning and mysterious feature that surrounds our majestic Sun.