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An accretion of steady flow for Gamma > 5/3?

  1. Nov 20, 2014 #1
    I would like to know, what happen with accretion (cloud) when drop toward a black hole. In Bondi case and terminology. If I understand:
    1) We describe the cloud falling to star (black hole) by EoS [itex]P(\rho)=K\rho^\Gamma [/itex].
    2) This accretion is steady it means [itex]\dot{M}=4\pi r^2u\rho=const. [/itex].
    3) Accretion to black hole is possible just for supersonic speed => solution of Bondi equation has to come through critical sound speed point.
    4) For [itex]\Gamma>\frac{5}{3} [/itex] doesnt exist critical point and accretion is not supersonic => no steady accretion on black hole for cloud with [itex]\Gamma>\frac{5}{3} [/itex].
    Are these 4 claims right?
    Bondi solution is dealing just with [itex]\Gamma<\frac{5}{3} [/itex]. It is quit hard constrain.
    My question are:
    a) What is the matter with cloud with [itex]\Gamma>\frac{5}{3} [/itex] during falling to black hole? Reaches the event horizon?
    b) How do we must change in assumptions for dealing with cloud with [itex]\Gamma>\frac{5}{3} [/itex]?
    I was checking in literature for this part of problem, but I didn't find anything important. Please let me know, comments or links.
    Thank you.
  2. jcsd
  3. Nov 25, 2014 #2
    Thanks for the post! This is an automated courtesy bump. Sorry you aren't generating responses at the moment. Do you have any further information, come to any new conclusions or is it possible to reword the post?
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