Smaller varieties of less than one solar mass also exist, but they are population II stars and are known as W Virginis stars.  
These stars generally have masses between 5 and 20 times that of the sun.  Smaller varieties of less than one solar mass also exist, but they are population II stars and are known as W Virginis stars.  Photon pressure causes these stars to rapidly expand in size; however, when the star has expanded, the pressure gradient is then too weak to counteract gravity, leading to contraction.  This occurs in a regular cycle dependent on the mass of the star.  FTP, name these stars with variable luminosity, used as a standard candle in making astronomical distance measurements.
These stars generally have masses between 5 and 20 times that of the sun.  
Cepheid variables