It seems like you're comparing the temperatures of different celestial objects, particularly the Sun and a red supergiant star like Stephenson 2-18.
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Sun: The core of the Sun reaches temperatures of approximately 27 million degrees Fahrenheit (15 million degrees Celsius). However, the surface of the Sun (photosphere) is around 10,000 degrees Fahrenheit (about 5,500 degrees Celsius).
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Stephenson 2-18 (St2-18): This is a red supergiant star. Supergiant stars, especially red ones, have much larger volumes than the Sun but can have cooler surface temperatures. The surface temperature of Stephenson 2-18 is roughly around 3,000 degrees Kelvin (about 2,727 degrees Celsius or 4,940 degrees Fahrenheit), which is cooler compared to the Sun's surface but has very high luminosity due to its size.
It’s important to clarify that while the core of the Sun is much hotter than the surface of both the Sun and Stephenson 2-18, the vast size of red supergiants like Stephenson 2-18 allows them to emit significant amounts of light and heat despite having lower surface temperatures than the core of smaller stars like our Sun. If there are specifics or additional comparisons you would like to discuss, feel free to ask!