Astrophysics and Space Science

, Volume 73, Issue 2, pp 349–353 | Cite as

The Jeans's instability in an expanding medium

  • J. P. Baptista
  • D. Gerbal


In this paper we solve, by the two time-scale method, the equation governing the evolution of a density perturbation in any expanding medium. The surprisingly simple result we obtain allows an accurate insight into the role played by cumulative but contradictory effects such as gravitational attraction forces and the expanding velocity field. Although the existence of a critical length is confirmed, there is no catastrophic growth of ‘instability’.


Velocity Field Attraction Force Density Perturbation Critical Length Simple Result 
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Copyright information

© D. Reidel Publishing Co 1980

Authors and Affiliations

  • J. P. Baptista
    • 1
  • D. Gerbal
    • 2
  1. 1.Laboratoire de physique théoriqueInstitut Henri PoincaréParisFrance
  2. 2.Groupe d'Astrophysique relativisteObservatoire de Paris-MeudonFrance

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