Labels:text | font | screenshot | document OCR: THE TERM BRIGHTNESS refers to a star's radiation at any or all wavelengths. For example, when a star's brightness increases, the star is likely to give off more infrared and ultraviolet radiation as well as more visible light. Apparent and absolute magnitudes, however, are measures of a star's visible-light brightness. The brightness of a star is determined principally by its mass and by which stage in its life cycle the star is at. The more mass a star has, the denser, hotter, and brighter it will be compared with a star of lower mass at a similar stage in its life cycle. Two stars of equal surface area and equal surface temperature have equal brightnesses and are the same color. If one star expands, its surface temperature drops. For example, a yellow main-sequence star such as the Sun e ...
