There is no planet in our solar system that is similar to the Sun. The Sun is a star, and planets are celestial bodies that orbit stars.

However, there are stars that are similar to the Sun in terms of:

* Size and mass: The Sun is a medium-sized star, and there are many other stars with similar properties.

* Temperature and luminosity: Stars can have different temperatures and luminosities, but there are many stars with similar values to the Sun.

* Composition: The Sun is mostly composed of hydrogen and helium, and there are many other stars with similar compositions.

So, while there is no planet like the Sun, there are many stars that share similar characteristics.