双星与变星研究组知识库

New V, R and I light curves of the short period binary system, HV Aqr, are presented. Photometric solutions were derived using the Wilson-Devinney code. Our new determined light curves do not show O'Connell effect. The nearly symmetry and complete eclipses of the light curves of HV Aqr enable us to determine high-precision photometric parameters of the binary system. The new solutions suggest that HV Aqr is a low mass ratio (q = 0.1455) deep contact binary with a contact degree off = 55.9%. Based on all available times of light minimum, we analyzed the long-term period changes of HV Aqr. A secular decrease rate of dP/dt = 8.84(+/- 0.18) x 10(-8) days yr(-1) was determined. The continuous period decrease can be explained by the mass transfer from the primary component to the secondary and angular momentum loss via magnetic stellar wind. A conservative mass transfer rate of dM(1)/dt = 1.81 x 10(-8)M(circle dot) yr(-1) and angular momentum loss rate at dJ/dt = 5.96 x 10(48) g cm(2) s(-1) yr(-1) were derived. As the orbital period decreases, the contact degree of HV Aqr will become deeper and finally it will evolve into a single rapid-rotation star. (C) 2012 Elsevier B.V. All rights reserved.