Labels:text | screenshot | font | number OCR: DISTANCE INDICATORS CEPHEID-VARIABLE stars are named after the first-known star of this type, Delta Cephei, which lies in the constellation of Cepheus. The period (length of time) a Cepheid star takes to pulsate once is an indication of its true brightness: the longer the period, the greater the brightness. By comparing the star's true brightness with its brightness as seen from the Earth, astronomers can calculate its distance. Cepheid stars are very bright and, in some galaxies, individual Cepheids can be seen. These stars provide astronomers with their most accurate method of establishing a galaxy's distance from the Earth.
