Altair is a bit larger than our Sun. Here's a breakdown of its size:

* Radius: About 1.8 times the radius of our Sun.

* Diameter: About 3.6 times the diameter of our Sun.

To put this in perspective:

* If the Sun were the size of a basketball, Altair would be about the size of a volleyball.

Altair is a bit denser than our Sun, making it a bit heavier as well, despite being slightly larger.