Stabilité vibrationnelle des étoiles en contraction durant les phases de combustion du deutérium

The pulsational stability with respect to the fundamen¬tal mode of radial pulsation of a 0.2M☉ star in the deutérium burning phase has been investigated, using the n=3/2 polytropic model. If the deuterium abundance in the prestellar material is greater than, or the same as the terrestrial value, the instability is significant. If, on the contrary, the initial deuterium abundance is smaller than the terrestrial value by a factor larger than 10, the amplitude of the pulsation increases too slowly to become significant. Any mass built on the n=3/2 polytropic model exhibits the same behaviour.