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Full-Text Articles in Physical Sciences and Mathematics
X-Ray Emission From O Stars, David H. Cohen
X-Ray Emission From O Stars, David H. Cohen
Physics & Astronomy Faculty Works
Young O stars are strong, hard, and variable X-ray sources, properties which strongly affect their circumstellar and galactic environments. After ~1 Myr, these stars settle down to become steady sources of soft X-rays. I use high-resolution X-ray spectroscopy and MHD modeling to show that young O stars like theta-1 Ori C are well explained by the magnetically channeled wind shock scenario. After their magnetic fields dissipate, older O stars produce X-rays via shock heating in their unstable stellar winds. Here too I use X-ray spectroscopy and numerical modeling to confirm this scenario. In addition to elucidating the nature and cause …
X-Rays From Magnetically Channeled Winds Of Ob Stars, In 'Magnetic Massive Stars', David H. Cohen
X-Rays From Magnetically Channeled Winds Of Ob Stars, In 'Magnetic Massive Stars', David H. Cohen
Physics & Astronomy Faculty Works
OB stars with strong radiation-driven stellar winds and large-scale magnetic fields generate strong and hard X-ray emission via the Magnetically Channeled Wind Shock (MCWS) mechanism. In this brief paper, I describe four separate X-ray diagnostics of the MCWS mechanism in OB stars, with applications to the prototype young O star, theta-1 Ori C.
Far-Off-Resonant Ring Trap Near The Ends Of Optical Fibers, Frank Moscatelli, C. Sackett, S. Du, E. Oh
Far-Off-Resonant Ring Trap Near The Ends Of Optical Fibers, Frank Moscatelli, C. Sackett, S. Du, E. Oh
Physics & Astronomy Faculty Works
We propose that micrometer-sized atom traps can be created using the optical dipole force between the ends of two single-mode optical fibers carrying counterpropagating light beams of two different wavelengths from both fibers. The traps have a simple design that is feasible to implement with commercially available products. They can be used as a flexible “atom tweezer” to manipulate atoms in free space without the need for traditional focused laser beams. A particularly interesting feature is the formation of a static ring-shaped trap for properly chosen beam parameters. Furthermore, this ring can be split into two longitudinally adjacent rings. Microscopic …
Periodic Accretion From A Circumbinary Disk In The Young Binary Uz Tau E, Eric L.N. Jensen, Saurav Dhital , '06, K. G. Stassun, J. Patience, W. Herbst, F. M. Walter, M. Simon, G. Basri
Periodic Accretion From A Circumbinary Disk In The Young Binary Uz Tau E, Eric L.N. Jensen, Saurav Dhital , '06, K. G. Stassun, J. Patience, W. Herbst, F. M. Walter, M. Simon, G. Basri
Physics & Astronomy Faculty Works
Close pre-main-sequence binary stars are expected to clear central holes in their protoplanetary disks, but the extent to which material can flow from the circumbinary disk across the gap onto the individual circumstellar disks has been unclear. In binaries with eccentric orbits, periodic perturbation of the outer disk is predicted to induce mass flow across the gap, resulting in accretion that varies with the binary period. This accretion may manifest itself observationally as periodic changes in luminosity. Here we present a search for such periodic accretion in the pre-main-sequence spectroscopic binary UZ Tau E. We present BVRI photometry spanning 3 …