Accretion disk structure

1
Accretion disk structure

• The accretion disk (AD) around a star can be
  considered as rings or annuli of blackbody
  emission. R is the stars radius.

2
Disk temperature

• Thus temperature as a function of radius T(R)

We define the boundary condition T at radius R

gt
3
Disk Luminosity

• The total energy available from the accretion of
  mass m onto M with radius R is
• But not all of this has to be lost (ie radiated
  from) the accretion disk there may be other
  processes involved

Eacc GMm R
4
Energy losses from the disk
R
Ebind 0
So the energy which has been lost in the disk by
m is
and Ldisk GMM 2R
Edisk GMm 2R
½Lacc