A linear and nonlinear study of Mira

Conference · Tue Dec 31 04:00:00 EST 1991

OSTI ID:10137346

Cox, A N ^[1]; Ostlie, D A ^[2]

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1. Los Alamos National Lab., NM (United States)
2. Weber State Univ., Ogden, UT (United States)

Both linear and nonlinear calculations of the 331 day, long period variable star Mira have been undertaken to see what radial pulsation mode is naturally selected. Models are similar to those considered in the linear nonadiabatic stellar pulsation study of Ostlie and Cox. Models are considered with masses near one solar mass, luminosities between 4000 and 5000 solar luminosities, and effective temperatures of approximately 3000 K. These models have fundamental mode periods that closely match the pulsation period of Mira. The equation of state for the stellar material is given by Stellingwerf procedure, and the opacity is obtained from a fit by Cahn that matches the low temperature molecular absorption data for the Population I Ross-Aller 1 mixture calculated from the Los Alamos Astrophysical Opacity Library. For the linear study, the Cox, Brownlee, and Eilers approximation is used for the linear theory variation of the convection luminosity. For the nonlinear work, the method described by Ostlie and Cox is followed. Results showing internal details of the radial fundamental and first overtone modes behavior in linear theory are presented. Preliminary radial fundamental mode nonlinear calculations are discussed. The very tentative conclusion is that neither the fundamental or first overtone mode is excluded from being the actual observed one.

• Research Organization: Los Alamos National Lab., NM (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 10137346
• Report Number(s): LA-UR--92-845; CONF-9107218--1; ON: DE92011265
• Country of Publication: United States
• Language: English

Related Subjects

661300
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CONVECTION
EQUATIONS OF STATE
LUMINOSITY
NONLINEAR PROBLEMS
OTHER ASPECTS OF PHYSICAL SCIENCE
SPECIFICATIONS
STAR MODELS
VARIABLE STARS