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Stothers, R.

Publications and source records attributed to Stothers, R..

At least 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

Nature of the secondary component of beta Lyrae.

Development of a hypothesis concerning the nature of the secondary component of beta Lyrae which is regarded as more plausible than the suggestion that this component is a black hole. Adopting Huang's (1962) and Woolf's (1965) basic model for beta Lyrae, it is suggested that the secondary star may be a massive 'main-sequence' star in rapid, nonuniform motion. Certain findings regarding mu Sco and V356 Sgr, which have primaries that are very cool and underluminous for their masses, are cited as evidence for such an inference, since their underluminosity is probably due to high angular momentum and they are normal enough not to be suspected of harboring a black hole.

Stothers, R.↗
NASA NTRS1972

Underluminosity and magnetic fields in Beta Lyrae

A combination of available observational data for Beta Lyrae and theoretical models of evolution in close binary systems in used to show that the minimum underluminosity of the dark secondary component of this system is 1 to 4 mag. It is demonstrated that magnetic fields are probably relatively weak in massive main-sequence stars, including the two stellar components of Beta Lyrae, and therefore that a strong magnetic field is not a likely explanation for the underluminosity of the secondary component of Beta Lyrae.

Stothers, R.↗
NASA NTRS1972

Stellar evolution of high mass based on the Ledoux criterion for convection

Theoretical evolutionary sequences of models for stars of 15 and 30 solar masses were computed from the zero-age main sequence to the end of core helium burning. During the earliest stages of core helium depletion, the envelope rapidly expands into the red-supergiant configuration. At 15 solar mass, a blue loop on the H-R diagram ensues if the initial metals abundance, initial helium abundance, or C-12 + alpha particle reaction rate is sufficiently large, or if the 3-alpha reaction rate is sufficiently small. These quantities affect the opacity of the base of the outer convection zone, the mass of the core, and the thermal properties of the core. The blue loop occurs abruptly and fully developed when the critical value of any of these quantities is exceeded, and the effective temperature range and fraction of the lifetime of core helium burning during the slow phase of the blue loop vary surprisingly little. At 30 solar mass no blue loop occurs for any reasonable set of input parameters.

Stothers, R.↗
NASA NTRS1972

Structure of massive main-sequence stars.

Core hydrogen-burning models are discussed together with the associated physical instabilities. A mathematical relation for dynamical instability is presented. Conditions leading to convective instability are analyzed, giving attention to the nature of the convectively unstable, chemically inhomogeneous, zone that is left behind by the retreating convective core. Questions of pulsational instability are also investigated.

Stothers, R.↗