Lawrence Anderson-Huang (Astrophysics)

Professor of Astronomy
Director, Ritter Planetarium
Ph.D., 1977, University of California at Berkeley

Dr. Anderson-Huang's research activities center on numerical simulations of radiative transfer and thermodynamic equilibrium in astrophysical situations, particularly in the atmospheres of the sun and stars in general. He has developed one of the only computer codes in the world capable of solving for the global equilibrium which determines the emerging spectrum of electromagnetic radiation from a star. Predictions from this code may be compared with actual observations in attempts both to understand physical processes within stellar atmospheres such as the radiative excitation of atoms, turbulence, and the dissipation of mechanical and magnetic energy, and to determine basic stellar parameters such as mass, radius, luminosity, and composition.

Applications of the code include work on the solar chromosphere and on the atmospheres of hot stars. We are able to resolve relatively small inhomogeneous structures on the sun. These structures dissipate their thermal energy through radiation and dynamic expansion, and their physical states may be determined by their radiative spectrum. Distant stars are too far away to resolve individual features, so one must rely more on theoretical simulations and regions of the spectrum which accentuate particular features (e.g. the infrared and/or ultraviolet).

As an outgrowth of his interest in radiative transfer problems, Dr. Anderson- Huang maintains collaborations and communication with atomic physicists, and works on problems concerning absorption and emission processes and electron and atom collision processes important for stellar atmospheres and interiors. He also maintains a continued interest in convection theory and modeling, and the signatures of convection imprinted on the emergent radiation spectra of stars.

Anderson, L., and Athay, R.G. 1989. Model solar chromosphere with prescribed heating. Ap. J. 346:1010.

A description of his code appears in: Kalkofen, W., ed. 1986. Numerical radiative transfer. Cambridge: Cambridge Univ. Press.


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