Vega is the fifth-brightest star in the night sky and is located in the constellation Lyra. It is a main sequence star, which means that it is still in the process of fusing hydrogen into helium in its core. Vega is about 25 times more luminous than the Sun and has a surface temperature of about 9,600 Kelvin. Vega is also a very rapidly rotating star, with a rotational velocity of about 274 kilometers per second at its equator. This rapid rotation has caused Vega to bulge at its equator and flatten at its poles, giving it an oblate spheroid shape.
Capella is the sixth-brightest star in the night sky and is located in the constellation Auriga. It is actually a binary star system, consisting of two stars that orbit around each other. The primary star in the Capella system is a yellow giant star, while the secondary star is a red dwarf. The primary star has a surface temperature of about 4,900 Kelvin and is about 11 times more luminous than the Sun. The secondary star has a surface temperature of about 3,500 Kelvin and is about 100 times fainter than the primary star. Capella is also a variable star, which means that its brightness varies over time.
So, the key differences between Vega and Capella are:
* Vega is a single star, while Capella is a binary star system.
* Vega is a main sequence star, while Capella is a yellow giant star and a red dwarf.
* Vega has a surface temperature of about 9,600 Kelvin, while Capella has a surface temperature of about 4,900 Kelvin for the primary star and 3,500 Kelvin for the secondary star.
* Vega is about 25 times more luminous than the Sun, while Capella is about 11 times more luminous than the Sun for the primary star and 100 times fainter for the secondary star.
* Vega has a rotational velocity of about 274 kilometers per second, while Capella has a rotational velocity of about 10 kilometers per second.