A star with a temperature of 30,000 degrees Celsius would be blue-white.

Here's why:

* Star Color and Temperature: The color of a star is directly related to its surface temperature. Hotter stars emit more blue light, while cooler stars emit more red light.

* Spectral Classes: Astronomers classify stars based on their temperature and spectral characteristics. Stars with surface temperatures around 30,000 degrees Celsius fall into the O spectral class, which is known for its blue-white color.

So, a star with a temperature of 30,000 degrees Celsius would be a very hot and luminous star, appearing blue-white in the night sky.