Abstract:
We have calculated the changes that would occur in mean intensity due to the presence of aberration and advection terms in radiative transfer equation. We have considered an absorbing medium with velocities 1000, 2000, 3000, 4000, and 5000 km s–/sup1 (β-0.0033, 0.017, where β =V/C,V is the velocity of the medium and C is the velocity of the light). Calculations have been done in a comoving frame with monochromatic radiation field. We have calculated the deviation in mean intensity defined as
J= {[J (V = O) – J (V > O)]/ J (V = O)] , where J is the mean intensity. We have taken two types of absorbing media (1) with a source of constant emission and (2) with emission source. As the emission decreases as 1/n 2 where n is the number of layer, where n=1 corresponds to ґ/Submax and n=N corresponds to =0 We find that for a total optical depth of one, the maximum change is about 2% when B(r)=1 and about 6%, when B(r) 1/n 2 where B(r) is the Planck function. When the optical depth increases to 5 the maximum change in the case of the constant source function falls to 1.5%, where as in the other case in which the Planck function changes as 1/r 2 the maximum changes remains at 6%. Further increase of the optical depth will reduce the changes to less than 2%. The amplification factor in the case of the Planck function varying as 1/r 2 is more than when the emission sources are constant.
