The residence time of dust grains in turbulent molecular clouds.
F. P. Pijpers;
AaA, 1997, 325, 300
ABSTRACT:The residence time of dust grains inside turbulent molecular clouds is calculated.
Earlier
estimates of this time by Boland & de Jong (1982ApJ...261..110B) have been
criticized by Prasad et al.
(1987, in "Interstellar Processes",
eds.
D.J.
Hollenbach, H.A.
Thronson, Kluwer, Dordrecht, 631) for not taking into account
properly the turbulent character of the velocity field in molecular clouds
which implies that the trajectory of a dust grain should be treated as a random
walk.
Taking some minimal assumptions regarding the turbulent velocity field a
time scale is derived that depends on the Reynolds number of the flow.
The
near proportionality with Reynolds number of this time scale results in a
much longer time scale over which dust grains will remain inside a molecular
cloud.
KEYWORDS: ism: dust, ism: molecular clouds, turbulence
PERSOKEY:turbulence, dust, size distribution, ,
CODE: pijpers97