Self-Similar Solution of Spherically Symmetrical Discontinuities with Increasing Energy in Generalized Roche Model

By use of the similarity method, the propagation of magnetogasdynamic spherical shock waves are discussed for Roche model in increasing energy medium. The effects of radiation heat flux on the discontinuities are also discussed. We have solve the differential equation by Runge-Kutta method and pattern of flow variables are illustrated by graphs.

Direct Observations of Rotationally Distorted Stars

We present infrared interferometric angular size measurements for rapidly rotating stars which indicate non-circular projected disk brightness distributions. For the A7IV-V star Altair, assuming that the apparent oblateness of the photosphere is due to the star's rapid rotation, a rigorous evaluation of the observation data in the context of a rigidly rotating Roche model shows that an estimate of v sin i = 210 ± 13 km s–1 can be derived that is independent of spectroscopic techniques. Altair is the first main sequence star for which direct observations of an oblate photosphere have been reported, and the first star for which v sin i has been established from observations of the star's photospheric geometry. Future prospects for this technique are considered, and a prospective catalog of 67 rotationally oblate targets is presented.

Surface Inhomogeneities on the W UMa star AC Bootis

New photometric data and two older data sets for AC Boo can be represented with a common set of Roche model parameters and two starspot pairs which drift only in longitude and are located on the cooler component.