Like the sun, Sirius is a star in the main sequence.However, Sirius is much shorter than the sun, and Sirius is only 240 million years old, and the sun is 4.6 billion years old.Whether it's mass or radii, or luminosity or surface temperature, Sirius is higher than the sun, and clearly much higher than the earth.Sirius is 2.06 times the mass of the sun, so its mass is 686 million times that of the earth.Sirius's radius is 1.71 times that of the sun, so its radius is 186 times that of earth.This means that Sirius can hold about 6.48 million earths, so Sirius is much bigger than earth.In view of the relationship between mass and volume, the density of Sirius obviously much smaller than the earth, the earth's density is 9.5 times the mass of Sirius, this is mainly because the earth is a relatively dense rocky planet, and Sirius is mainly composed of hydrogen and helium plasma planet.
In addition, Sirius is a very bright star with a surface temperature close to 10,000 degrees kelvin.By comparison, the average surface temperature of the earth is about 288 degrees kelvin, or about 15 degrees Celsius.On the other hand, Sirius's surface gravity is about 20 times that of the earth.Like earth, Sirius will rotation, Sirius in the rotation of the equator, linear velocity of 16 km/s, and the earth at the equator the rotation speed of only 0.465 km/SEC, far slower than Sirius.
Sirius is very visible in the night sky, and around it there is actually a very inconspicuous companion, Sirius B, a White Dwarf that cannot be seen with the naked eye.Sirius B is a star that has evolved to the final stage, and in the distant future our sun will be like this.
