Kenneth Gayley

WR104: Click for animation

WR104 is the prototype pinwheel nebula. Powering the heart of the system are a pair of luminous hot stars locked in a binary orbit. (Tuthill et al. 2008)

Effective aperture for detection of UHE neutrinos impacting the Moon (Gayley, et al. 2009. ApJ, 706,1556.)

Associate Professor

Ph.D., Astrophysics, University of California at San Diego 1990

Contact Information

Department of Physics and Astronomy

University of Iowa, 707 Van Allen Hall

Phone: 319-335-3282, FAX: 319-335-1753

Email: kenneth-gayley [at]

Personal home page:

Biographical Information

I grew up in Buffalo, N.Y.,and attended Princeton University (A.B. Physics, 1983).  I went on to study solar physics at U. C. San Diego and at the Institute for Astronomy in Honolulu.  After one post-doc in cool star spectroscopy at the University of Colorado and another in hot-star wind dynamics at the University of Delaware, I joined the faculty at the U. of Iowa in 1997.  On the personal side, I have long enjoyed playing Ultimate frisbee, but starting a family has more recently dominated my activities away from work.

Research Interests

My current research interests center on radiative transfer in stellar atmospheres, primarily the supersonic winds of very hot stars where the radiation is actually the dominant driver of mass motions.  The Sun has a wind too, but on the scale of a hot star it is like a drippy faucet compared to the Niagara Falls!  Hot stars are continuously experiencing the stripping of their outer layers, and in some cases lose a significant amount of their mass over their evolutionary lifetime.  I also study binary hot stars and the violent collisions of their winds.

Recently I have extended my interests to the X-rays emitted by these violent collisions, eitherbetween winds or within individual winds.  The usual approach to doing this is to try to infer the distribution of hot gas that generates the X-rays, but I prefer to try to model the heating process directly, rather than via its hot-gas middleman, because I have found that the hot gas distribution cannot be known unambiguously, and in any event it is the heating we wish to understand.I also model the circularly polarized spectra of winds threaded with strong magnetic fields, as the magnetic fields can play a role in causing wind streams to collide.

The unifying thread throughout my interests is the way we use light to learn about astrophysical phenomena, and my approach is generally to fill what I perceive is an important niche that connects the qualitative and conceptual features between both models and observations.  I feel this kind of bridging brings insight and clearer communication  across the divide between these often rather disparate disciplines, a bridge that can get lost in those devilish details.

Selected Publications

Gayley, K, and Ignace, R. 2010, The Zeeman Effect in the Sobolev Approximation: Split Monopole Fields and the "Heartbeat" Stokes V Profile, ApJ, 708,615.

Jaeger, T., Mutel, R., and Gayley, K. 2010, Project RESUN, a Radio EVLA Search for UHE Neutrinos, Astroparticle Physics, doi:10.1016/j.physletb.2003.10.071

Gayley, K. G., Mutel, R. L., & Jaeger, T. R. 2009, Astrophysical Journal, Analytic Aperture Calculation and Scaling Laws for Radio Detection of Lunar-Target UHE Neutrinos, 706, 1556.

Gayley, K. G.  2009, Asymptotic Opening Angles for Colliding-Wind Bow Shocks: The Characteristic-Angle Approximation, ApJ, 703,89.

Tuthill, P., Monnier, J., Lawrance, N., DAnchi, W., Owicki, S., Gayley, K. 2008, The Prototype Colliding-Wind Pinwheel WR 104, ApJ 675, 698.

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