On the Vibrational Stability of Gaseous Stars.

The dependence of the vibrational stability of stars upon their masses has been investigated, and it has been established that for laws of generation of energy of the type of Bethe's law, the ordinary law of opacity and a ratio of the specific heats of matter ~y equal to ~, some instability would first appear for masses larger than iooM0. Changes in the law of opacity as well as in the ratio of the specific heats are more likely to occur in the outer layers of the stars, and their effects on the stability, especially for the giants, can be important. If the region where they occur is appropriately chosen, these changes could render the star unstable for one of the higher modes (first or second), although it remains stable for the preceding ones. Some at- tention was also paid to the stability of "shell-source" and "ball-source" models with the conclusion that they would not exhibit any special instability