Stellar evolution at high mass with convective core overshooting
Convective overshooting beyond the formal boundary of a convectively unstable stellar core is studied here in terms of a free overshoot parameter d/H/sub p/ (overshoot distance divided by local pressure scale height) in order to determine in more detail than previously the effect of widespread convective core mixing on the main-sequence evolution of stars in the mass range 15-120 M/sub sun/. For values of d/H/sub p/ within a critical range that depends sensitively on stellar mass, an evolving star expands its radius enormously and can become a red supergiant before the end of core hydrogen burning if M> or =60 M/sub sun/. Since convective instability in the envelopes of main-sequence stars more massive than approx.15 M/sub sun/ is only partly suppressed by convective core overshooting, the unresolved problem of semiconvection in the chemically inhomogeneous zone still exists (except in cases where mass loss is sufficiently heavy to suppress the instability).
- Research Organization:
- Institute for Space Studies, NASA/Goddard Space Flight Center
- OSTI ID:
- 5516267
- Journal Information:
- Astrophys. J.; (United States), Vol. 292:1
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GENERAL PHYSICS
MAIN SEQUENCE STARS
STAR EVOLUTION
CONVECTION
HERTZSPRUNG-RUSSELL DIAGRAM
HYDROGEN BURNING
STAR MODELS
STELLAR WINDS
DIAGRAMS
ENERGY TRANSFER
HEAT TRANSFER
MASS TRANSFER
MATHEMATICAL MODELS
STAR BURNING
STARS
STELLAR ACTIVITY
640102* - Astrophysics & Cosmology- Stars & Quasi-Stellar
Radio & X-Ray Sources