W Virginis (also SAO 139335, and HD 116802) is a giant yellow pulsating star, which varies between magnitudes 9.46 and 10.75 over a period of 17.2736 days. The star is located 11,000 light-years away in the constellation Virgo. The star is the prototype variable star, that exhibit pulsation periods between 10-20 days, for the population II cepheids, and are of spectral class F6 - K2. Type II Cepheids are divided into groups according to their period. The stars with a period between 1 and 5 days are called the BL Herculis class, periods between 10-20 days are the W Virginis class, and greater than 20 days are the RV Tauri class. Type II cepheid variables generally have low metallicities, a mass of less than 1 solar mass, and are on average 1.5 magnitudes fainter than Type I Cepheids. The variables have a distinctive 0.3 to 1.2 magnitude variation in the light curve with a bump on the decline.
W Virginis was discovered by German astronomer Eduard Schönfeld using a small refractor at the Mannheim observatory in Germany, on the 7th April 1866.
Right ascension 13h 26m 01.99307s, Declination -03° 22' 43.4164"
