In 1960,L. Binnendijk interpreted the particular shape of thelight curve for AH Vir as being due to a sub-luminous region on the primary.[15] Multiple observers noted frequent changes to the light curve and period over time, and in 1977G. A. Bakos foundemission in the calciumK line that suggested mass transfer is taking place.[16] Theamplitude of these changes compared to the overall brightness variation is among the largest known among W UMa-type variables. The primary eclipse is total with a duration of around 43 minutes.[17] It was proposed in 1991 that the observed variations in the light curve may be caused bymagnetic activity and magnetic interactions between the components.[18]
There has been uncertainty as to whether the two stars are in direct contact with each other, or if the system issemi-detached with only the primary being close to itsRoche lobe. The evidence now suggests that they are anovercontact system. Theorbital period is showing an increase over time of(2.1869±0.0161)×10−7 d·yr−1, combined with a cyclical variation with a period of 37.19 years. The system shows a strong level ofmagnetic activity,[19] with the primary being the more active component.[4] The mean magnetic field strength of the primary is estimated as1.487 kG. The cyclical variation in orbital period may be related to the activity on the primary.[19]
^abcdefLu, W. -X.; Rucinski, S. M. (July 1993), "Spectral-Line Broadening Functions of W UMa-Type Binaries. II. AH Vir",Astronomical Journal,106: 361,Bibcode:1993AJ....106..361L,doi:10.1086/116645.
^Hussey, William Joseph (1905), "Observations of one hundred new double stars : eleventh catalogue",Lick Observatory Bulletin,81, Berkeley: The University Press:151–158,Bibcode:1905LicOB...3..151H,doi:10.5479/ADS/bib/1905LicOB.3.151H. Identified as HU 1137.
^Chang, Y. C. (January 1948), "Spectrographic Observations of the Eclipsing Binaries of the W Ursae Majoris Type: AH Virginis and TZ Bootis",Astrophysical Journal,107: 96,Bibcode:1948ApJ...107...96C,doi:10.1086/144990.
^Bakos, G. A. (1977), "Variations of the Light Curve and the Period of AH VIR",Bulletin of the Astronomical Institute of Czechoslovakia, vol. 28, p. 157,Bibcode:1977BAICz..28..157B.
^Kaluzny, J. (1984), "Determination of parameters of W UMa-type systems : V757 Cen, GW Cep, BX Peg, AH Vir",Acta Astronautica,34:217–224,Bibcode:1984AcA....34..217K.
Niarchos, P. G. (July 1983), "Light curves and elements of AH Virginis",Astronomy and Astrophysics Supplement Series,53:13–19,Bibcode:1983A&AS...53...13N.
Hoffmann, M. (March 1981), "B and Mg Band Observations of AH Vir in 1977",Information Bulletin on Variable Stars,1933: 1,Bibcode:1981IBVS.1933....1H.
Hopp, U.; Witzigmann, S. (August 1981), "Note on the Period of the W UMa Star AH Vir",Information Bulletin on Variable Stars,2005: 1,Bibcode:1981IBVS.2005....1H.
Sievers, J. R. (October 1963), "A Photoelectric Study of AH Virginis",Publications of the Astronomical Society of the Pacific,75 (446): 446, 418,Bibcode:1963PASP...75..418S,doi:10.1086/127995.
Kitamura, M.; et al. (1957), "Photoelectric Observations of AH Virginis and the Interpretation of its Color Changes at Light Minima",Publications of the Astronomical Society of Japan,9: 119,Bibcode:1957PASJ....9..119K.
