CHARA Array K ′ - band Measurements of the Angular Dimensions of Be Star Disks

We present the first K -band, long-baseline interferometric observations of the northern Be stars γ Cas, φ Per, ζ Tau, and κ Dra. The measurements were made with multiple telescope pairs of the CHARA Array interferometer, and in every case the observations indicate that the circumstellar disks of the targets are resolved. We fit the interferometric visibilities with predictions from a simple disk model that assumes an isothermal gas in Keplerian rotation. We derive fits of the four model parameters (disk base density, radial density exponent, disk normal inclination, and position angle) for each of the targets. The resulting densities are in broad agreement with prior studies of the IR excess flux and the Current address: Physical Sciences Department, Embry-Riddle Aeronautical University, 600 S. Clyde Morris Blvd., Daytona Beach, FL 32114