From Stardust to Planetesimals: Contributed Papers - NASA Lunar ...

0oo^OoOO® o0 ® ® a o 00a0 ® Z7O o®nFigure 2. Contour plot of V536 Aql in J, H and K (from the left to the right) in August 1993 (above)and April 1994 (below). The contours are at: 0.5 - 1 - 2 - 3 - 4 - 5 - 6 - 7 - 8 - 9 - 10 - 50 and 100 %of the maximum peak value.If we are dealing with a viscous accretion disk that liberates gravitational energythrough dissipative processes, and if the disk masses are small compared to the respectivecentral star's mass (see e.g. Beckwith 1994), we get local effective temperaturesin the disk of:M 1/4 Mr -3/4Tef f, disk(^ = 150 K ) (1)ME) ( 10- 7Mo/yr 1 AUM*: mass of the accreting star; M: mass accretion rate; r distance to the accretor).or pre-main sequence accretion disks, the mass flow rate is typically of the orderof 10-7Mpl yr, leading to Teff,disk in the range of 150 K (at r = 1 AU) to 10 K (at40 AU). The bulk of the radiation of such an accretion disk will be observable in thesub-mm wavelength range. Thus the currently available observations do not allow usto confirm or to rule it out.1/44. AN ALTERNATIVE EXPLANATION: OPTICALLY THICK CON-DENSATIONS AROUND ONE OR BOTH COMPONENTS4.1. Physical description of the modelBesides of the two stars, we have two more ingredients in our model that play importantroles: spatially resolved circumstellar material that is visible and that showsstrong indications for variability and optically thick condensations around one or bothcomponents of the binary system. In the following, we will simply call them `blobs' or