This is classified as atype II Cepheid of theBL Her type,[11] having a short pulsation period of 1.348 days.[2] However, a 2014 survey has it classified as an anomalous Cepheid of theBL Boo type.[12] Thelight curve is asymmetrical, resembling that of a typeabRR Lyrae variable. On theHR diagram it is positioned above thehorizontal branch. For this reason, it is sometimes used as the prototype of, "Above Horizontal Branch variables of subtype 1."[13]
This is a very metal-poor star[8] with an estimated 0.6 times the mass of the Sun. Theeffective temperature and radius vary depending on the phase of the pulsation cycle.[6]
^ab"XX Vir".International Variable Star Index.AAVSO. Retrieved2025-11-28.
^Duflot, M.; et al. (1995), "Radial velocities: The Wilson-Evans-Batten catalogue",Astronomy and Astrophysics Supplement Series,114: 269,Bibcode:1995A&AS..114..269D.
^Smith, Horace A.; et al. (August 1978), "Strömgren photometry of field BL Herculis stars. I. BL Herculis and XX Virginis",Publications of the Astronomical Society of the Pacific,90:422–428,Bibcode:1978PASP...90..422S,doi:10.1086/130351.
