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Disk Instabilities in Hubble-Sandage Variables?

Published online by Cambridge University Press:  12 April 2016

F. Meyer
Affiliation:
Max-Planck-Institut für Physik und Astrophysik, Institut für Astrophysik, Karl-Schwarzschildstr. 1, 8046 Garching bei München
E. Meyer-Hofmeister
Affiliation:
Max-Planck-Institut für Physik und Astrophysik, Institut für Astrophysik, Karl-Schwarzschildstr. 1, 8046 Garching bei München

Extract

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The brightest individual objects in extragalactic nebulae are the Hubble-Sandage variables. They were first investigated by Hubble and Sandage (1953). Observations by Tamman and Sandage (1968) and Rosino and Bianchini (1973) followed. The main characteristics are high luminosity (L/Lʘ ≈ 105), blue color indices, F type spectra and irregular variability.

Bath (1979) has suggested that the Hubble-Sandage variables contain an accreting main-sequence star with a Roche Lobe filling companion in a wide binary system. Based on this model we derive theoretical color indices for disks and determine the mass in the disk for different mass accretion rates. Further we discuss an instability of the disk which could explain the change in the color index observed for Var A in M33.

Type
Part I: Evolution of Stars in the Post-Main Sequence Stage
Copyright
Copyright © Reidel 1982

References

Allen, C.W.: 1973, Astrophysical Quantities, The Athlone Press University of London, third edition.Google Scholar
Bath, G.T.: 1979, Nature 282, 274.Google Scholar
Meyer, F., Meyer-Hofmeister, E.: 1981, Astron. Astrophys. in press.Google Scholar
Hubble, E., Sandage, A.: 1953, Astroph. J. 118, 353.Google Scholar
Rosino, L., Bianchini, A.: 1973, Astron. Astrophys. 22, 453.Google Scholar