| Popis: |
Many eclipsing variables exhibit characteristics that indicate lack of stability. Physically, these systems range from certain short-period dwarfs, which show irregular brightness fluctuations unexplainable by any normal eclipse hypothesis, to systems such as AO Cassiopeiae: class O super-giants whose periods, velocity curves, and light curves have shown remarkable variations. Included are systems having one Wolf-Rayet component and probably one old nova. Many eclipsing binaries show erratic changes of period that are difficult to explain on any concept of a stable system. Indeed, when we consider the physical conditions which must prevail when two stars are located with their surfaces only a few hundred thousand miles from each other, perhaps we should be surprised that the irregularities are not larger. |
