FTP, what are these pulsating variable stars?
John Goodricke discovered delta prototype of this type of star in 1784. The exceptional RR Lyrae type hinders its main use, which derives from the fact that its size fluctuates anywhere from 7 to 15 percent, allowing them to be used to determine stellar distances using their period-luminosity law, discovered by Henrietta Leavitt. FTP, what are these pulsating variable stars?
John Goodricke discovered delta prototype of this type of star in 1784.
Cepheid Variable Stars