How hot are the Sun’s core and photosphere?

The temperatures of the Sun vary significantly between its interior and its surface:

• Core: The temperature at the center of the Sun is approximately 15 million kelvin (27 million °F). This extreme heat is necessary to facilitate nuclear fusion, the process that powers the Sun by converting hydrogen into helium.12
• Photosphere: The surface of the Sun, known as the photosphere, reaches a temperature of about 5,800 kelvin (10,000 °F). This is the layer from which most of the Sun's radiation is emitted into space.12

While the temperature drops as one moves from the core toward the photosphere, it is notable that temperatures begin to rise again in the outer layers of the Sun's atmosphere, such as the chromosphere and the corona.12