Nebular characteristics of NGC 7293

NGC 7293 is a spiral nebula produced by a sun-like star at the end of its life, and it is the closest planetary nebula to us. The outer gas shell of this star was thrown into space. From the position of the earth, it looks like it is in a spiral staircase. The remnants of the star core destined to become white dwarfs emit very high energy radiation, which causes the previously ejected clouds to fluoresce. The spiral nebula is located in Aquarius in the northern sky, with a size of about 2.5 light years and a distance of about 650 light years. From the close-up image of the inner region of the spiral nebula, we can find that it has many complicated cloud gas knots with unknown reasons.