Be star disc characteristics near the central object

ZOREC, J.; ARIAS, M. L.; CIDALE, L.; RINGUELET, A.

ASTRONOMY AND ASTROPHYSICS

EdP Sciences

Lugar: Les Ulis ; Año: 2007 vol. 470 p. 239 - 247

0004-6361

A recent analysis of visual Fe II emission lines of 17 classic Be stars using the self-absorption curve method (SAC) revealed that these lines are optically thick and they form in circumstellar disc (CD) regions within two stellar radii from the central star on average. The aim of this paper is to study the physical characteristics of CD regions situated close to the star. We used the Fe II emission line optical depths derived for a sample of the above mentioned classic Be stars that are seen either nearly pole-on or equator-on. The disc properties sought are then inferred by reproducing the average pole-on and equator-on optical depths using simple CD models with different density and temperature distributions.We found that the CD regions near the star, which account for the average Fe II line opacities obtained with the SAC method, have semi-height scales perpendicular to the equatorial plane higher than 0.5 stellar radii and particle density distribution laws N(R)=No(Ro/R)^n with n