Look up and you will see many twinkling stars in the sky. A point of light eg. Apparently, you will think that it is one star, but do you know that it is not one star that you see, but actually two stars that are orbiting each other, i.e. rotating around each other.

 Two or more such stars that revolve around each other are called binary stars or binary stars. According to an estimate, ten percent of the stars in the sky are actually binary stars. Among these binary stars, we only see the star that is the brighter of the two. For example, the Polaris, which appears to be a single star, is actually a system of three stars, the brightest of which we see, Polaris A, has a mass equal to 5.4 Suns, while the other two stars that revolve around it are slightly more massive. The smaller ones, namely Polaris b and Polaris Ab, which have a mass of about one time that of the Sun, are not visible to the naked eye. They require a telescope. 

Similarly, our Earth's nearest neighbor, Alpha Centauri A, which is 4.36 light-years away, is actually a binary star system with another star, Alpha Centauri B, which is slightly smaller. And less bright, these two are also revolving around each other.

Binary stars can orbit each other at close distances or at great distances. If two stars are orbiting very close to each other, one star can even swallow the other star's material due to its gravity. Some binary star systems remain in perfect equilibrium and do not collide, but there are also many binary systems in which the stars eventually collide.

According to an estimate, two stars collide in the center of our galaxy every ten thousand years. 

In 2008, scientists first observed the collision of two stars. In the same year 2022, there is a possibility that a binary star system KIC 9832227.

The two stars in I will collide with each other. They are about 1843 light-years away from Earth and their collision will throw off enough light that a new star will be added to the Earth's sky with the brightness of the Pole Star.