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Static and dynamical models of long-period variable stars


Keeley, Douglas Allan (1970) Static and dynamical models of long-period variable stars. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/NTN2-HH47.


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The parameters of the models were M=1 and 1.3M[...], M[subscript B] = -3.8 to -5, and T[subscript e] = 2200[...]K. The equation of state included a detailed calculation of ionization equilibrium and the dissociation of H2, OH, CO, and H2O. The opacity of CO, OH, and H2O was included. The dynamical calculations show that large-amplitude pulsation can occur in convective models. The opacity mechanism causes strong driving of the pulsation in the region outside the hydrogen ionization zone, and the [gamma]-mechanism results in very low dissipation in the hydrogen zone. The phase relation between the bolo-metric luminosity and the radius variations is similar to that of Cepheids. The static models have large ionization and dissociation zones, which cause the pulsation parameter Q=P[subscript days](p/p[...])[...] to become greater than 0.15 in some models. The fundamental periods range from 180 days to greater than 2000 days; the overtone periods are about [...] as long. The positions of many observed stars in the theoretical HR diagram suggest that their periods should be associated with the overtone periods of the models.

Item Type:Thesis (Dissertation (Ph.D.))
Degree Grantor:California Institute of Technology
Division:Physics, Mathematics and Astronomy
Major Option:Astronomy
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Goldreich, Peter Martin
Group:Astronomy Department
Thesis Committee:
  • Unknown, Unknown
Defense Date:10 September 1969
Record Number:CaltechETD:etd-05072008-142808
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:1665
Deposited By: Imported from ETD-db
Deposited On:09 May 2008
Last Modified:21 Dec 2019 04:06

Thesis Files

PDF (Keeley_da_1970.pdf) - Final Version
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