No, a star cannot be so hot that its color becomes black. The color of a star is determined by its surface temperature, and it follows a specific sequence known as the Hertzsprung-Russell diagram. The color of a star ranges from red for cooler stars to blue for hotter stars, with various shades of orange, yellow, and white in between.
As the temperature of a star increases, it emits more energy across a broader range of wavelengths, including visible light. Extremely hot stars emit a significant amount of ultraviolet radiation as well. However, even the hottest stars still emit some visible light, although they may appear more blue or bluish-white in color rather than red or yellow.
Black objects, on the other hand, absorb all colors of light and do not reflect or emit any visible light. Therefore, a star cannot be so hot that it appears black.