# Climate of a Planet in a Binary Star System

Would the climate of a planet in a binary star system consisting of a K star and a G star be affected by the binary system? By this I mean, does having two stars at the center of a solar system affect the climate of the planets around it as opposed to having just one? (The stars are close together).

A G star is sunlike, with a mass of anywhere between .8 and 1.04 solar masses, and the K star is smaller, with a mass of anywhere between .45 and .8 solar masses. Let's assume that the G star is just like the Sun, and the K star has a mass of .75 solar masses. More clarity would be needed, but I am able to work with small amounts of information. For a stable orbit around a shared center of mass, we will assume that the orbital radius is 1.5 million km. They will revolve around each other every .2772 days, which means that they orbit each other at about 394 km/s. If we take the Solar System as it is, and give it the smaller sun in a close, stable orbit around the larger sun, the orbits of the planets will be more eccentric, as well as them having shorter years, in order for the orbits to be stable.

For example, Earth (or any planet in your system that orbits at 1 AU) will have a year that's about .756 Earth years long. That's about 276.1 Earth days. As for temperature, a star with 75% of the Sun's mass would be releasing about 36.5% of the energy the Sun releases. That means that the luminosity of the system is 1.365 times that of our own, which is the same luminosity as a single star with a mass of approximately 1.09 solar masses. That means that if Earth was in the system, with an orbital radius of 1 AU, then its average temperature would be 307 K, which is a good amount warmer than what we're used to, but can still support life. The habitable zone would be moved further out, because of the increased luminosity of the binary system, as well as fluctuating solar gravity increasing orbital eccentricity.

• Thanks! I'm sorry for the lack of information, but I don't really know much about this and I haven't figured it out for my world. Are there any resources you could recommend or things that I should figure out or take into consideration? Commented Apr 11, 2021 at 23:20
• Specifying an approximated mass of each star, an orbital radius for the two stars, and the orbital radius of at least one of the planets in the system would do. Commented Apr 12, 2021 at 0:41