It is ice crystals in the atmosphere that causes this. I have seen it a few times during my life, and I am 56 years old.
I have even seen a full circle around the sun, as it was high in the sky, and not near the horizon
You can see something similar around the moon at times. A small sphere of light surrounding it.
I suspect this is will become more common, as time goes by. Because of the whitening of the sky generally, from the exhaust from airplanes in the upper troposphere, and stratosphere. The ice is created by particles that it can bind to
edit: that small green dot to the left of the sun is lens refraction. At 1/3 distance compared to the ice ring