It's tricky to say definitively which star is the absolute most similar to our Sun, as there are many factors to consider. But, a strong contender for the title is 18 Scorpii.

Here's why:

* Spectral type: 18 Scorpii is a G2V star, just like our Sun. This means they have similar surface temperatures and luminosity.

* Size and mass: 18 Scorpii is very similar in size and mass to our Sun.

* Age: It is slightly older than our Sun, but not by much.

However, there are other stars with similarities to our Sun:

* Kepler-452b: While not a star itself, this planet orbits a star very similar to our Sun, making it a promising candidate for hosting life.

* Tau Ceti: This star is slightly smaller and cooler than our Sun, but still within a similar range. It has a few planets orbiting it, but none have been confirmed to be in the habitable zone.

Ultimately, the search for Sun-like stars is ongoing, and new discoveries are constantly being made.