Line-Driven Winds Revisited in the Context of Be Stars: Ω-slow Solutions with High k Values

Jessie Silaj(1), Michel Cure(2), Carol E. Jones(1)

(1) Department of Physics and Astronomy, The University of Western Ontario, Canada
(2) Instituto de Fisica y Astronomıa, Universidad de Valparaıso, Chile

The standard, or fast, solutions of m-CAK line-driven wind theory cannot
account for slowly outflowing disks like the ones that surround Be stars. It
has been previously shown that there exists another family of solutions --- the
$Omega$-slow solutions --- that is characterized by much slower terminal
velocities and higher mass-loss rates. We have solved the one-dimensional m-CAK
hydrodynamical equation of rotating radiation-driven winds for this latter
solution, starting from standard values of the line force parameters ($alpha$,
$k$, and $delta$), and then systematically varying the values of $alpha$ and
$k$. Terminal velocities and mass-loss rates that are in good agreement with
those found in Be stars are obtained from the solutions with lower $alpha$ and
higher $k$ values. Furthermore, the equatorial densities of such solutions are
comparable to those that are typically assumed in ad hoc models. For very high
values of $k$, we find that the wind solutions exhibit a new kind of behavior.

Reference: ApJ 795, 78 (2014)
Status: Other