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Z Cha – Another Case of Gravitational Radiation?

Published online by Cambridge University Press:  12 April 2016

H. Ritter
H. Ritter*
Affiliation:
Max-Planck-Institut für Physik und Astrophysik, München

Extract

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By combining spectroscopic data obtained by Vogt (1979) and photometric data obtained by Bailey (1979) and Fabian et al. (1979) it is possible to determine the physical parameters of the southern dwarf nova Z Cha (Ritter, 1979). The resulting values are: mass of the white dwarf primary M1=(0.035±0.06)M⊙, radius of the white dwarf R1=(1.8 10-2)R⊙, mass of the secondary M2=(0.16±0.02)M⊙, radius of the secondary R2=(0.19±0.01)M⊙, inclination i = 748±0.8°. Accordingly the primary conforms to the theoretical M-R relation of white dwarfs and the secondary to the theoretical low mass main sequence. The mass exchange rate derived from the luminosity of the accretion disk and from the hot spot respectively turns out to be Ṁ ≈ 4.10-11 M⊙/year, about 102 times more than is expected from the nuclear evolution of the secondary. On the other hand, angular momentum losses due to gravitational radiation predicts a mass loss rate (Faulkner, 1971) which is almost identical to the one derived from observations. Therefore after the binary pulsar (Taylor et al., 1979), Z Cha seems to be another case presenting strong evidence for the action of gravitational waves.

Type
Abstracts of Workshop Papers on Dwarf Novae
Information
International Astronomical Union Colloquium , Volume 53: White Dwarfs and Variable Degenerate Stars , August 1979 , pp. 503
Copyright
Copyright © The University of Rochester 1979

References

Bailey, J.A. 1979, Monthly Notices Roy. Astron. Soc., 187, 645 Google Scholar
Fabian, A.C., Pringle, J.E., Whelan, J.A.J., and Bailey, J.A. 1979, Proceedings of the IAU Colloquium No. 46, eds. Bateson, F.M., Smak, J.I., and Urch, I.H., Hamilton, University of Waikato Press, in press.Google Scholar
Faulkner, J. 1971, Astrophys. J. Letters, 170, L99.Google Scholar
Ritter, H. 1979, Nature, in press.Google Scholar
Taylor, J.H., Fowler, L.A., and McCulloch, P.M. 1979, Nature, 277, 437.Google Scholar
Vogt, N. 1979, Mitt. Astron. Ges., in press.Google Scholar