New strong evidence for the importance of convective overshooting in intermediate-mass stars
- Universitetets Astronomiske Observatorium, Tollose (Denmark) Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (USA)
Major differences between current series of stellar evolution calculations concern their opacities and treatment of convection. Accurate mass, radius, luminosity, and abundance data from eclipsing binaries now allow significant conclusions on these differences: binary stars with small convective cores are very well fitted by standard models using Los Alamos (but not Cox-Stewart) opacities. However, at just slightly larger masses, the moderately evolved binaries clearly require convective overshooting for a satisfactory fit. Precise radial velocities for F-type turnoff stars in IC 4651 and NGC 3680 not only confirm the signatures of overshooting observed in these clusters but also show that any such firm conclusions require proper identification of binaries and nonmembers. It is concluded that standard (and some overshooting) models are inconsistent with current precise data for intermediate-mass stars. Among the consequences of rejecting the older models, it is pointed out that ages for stars younger than roughly 4 Gyr will increase by up to 50-100 percent. 27 refs.
- OSTI ID:
- 6164026
- Journal Information:
- Astrophysical Journal; (USA), Vol. 363; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GENERAL PHYSICS
STAR EVOLUTION
CONVECTION
OPACITY
BINARY STARS
ECLIPSE
ELEMENT ABUNDANCE
HERTZSPRUNG-RUSSELL DIAGRAM
MASS
STAR CLUSTERS
STAR MODELS
ABUNDANCE
DIAGRAMS
ENERGY TRANSFER
HEAT TRANSFER
MASS TRANSFER
MATHEMATICAL MODELS
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
STARS
640102* - Astrophysics & Cosmology- Stars & Quasi-Stellar
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