Sirius A is a main sequence star, similar to the sun, but larger than the sun, with a diameter of about 2.5 million kilometers, which is 1.8 times the diameter of the sun. The mass is about 2.1 times the mass of the sun. The surface temperature is about 10,000 degrees, so it is white.

The following is the size ratio of the Sun and Sirius A. You can also see the size comparison between the Sun and Jupiter, the largest planet in the solar system.

Sirius B is a white dwarf star, forming a pair of binary stars with Tianmao Star A, orbiting each other. The mass of Tianmao Star B is slightly larger than that of the sun, but its diameter is smaller than that of the Earth, only about 9,600 kilometers; the surface temperature is about 25,000 degrees, more than twice as high as that of Tianmao Star.

The following is the size of Sirius B compared to the Earth.

The following is the size ratio of the eight major planets.