What is the approximate core temperature of the Sun based on solar models?

$15 imes 10^6$ Kelvin ($15$ million K)

Solar models tracking energy balance and neutrino production estimate the central region of the Sun maintains a temperature of approximately $15 imes 10^6$ Kelvin. This specific temperature level is critically important because it provides exactly the necessary conditions to sustain the ongoing nuclear fusion process. This fusion reaction involves converting hydrogen into helium, which serves as the primary, continuous fuel source that powers the Sun throughout its stable main-sequence existence. While other stars possess vastly higher core temperatures, the Sun's $15$ million K is the stable baseline required for its long-term energy output.