We discuss the feasibility of using solar-type main-sequence stars as probes of fundamental physics and unification. We use a simple polytropic stellar structure model and study its sensitivity to variations of the gravitational, strong and electroweak coupling constants in the context of unification scenarios. We quantify the sensitivity of the Sun's interior temperature to these variations, finding $|Δα/α|\lesssim1.3\times10^{-4}$ for a 'canonical' choice of unification scenario, and discuss prospects for future improvements.

6 pages, 2 figures; submitted to Phys. Rev. D