Radiative Torque and Partial Spin-Down of Winds from Rotating Hot Stars

Details Radiative Torque and Partial Spin-Down of Winds from Rotating Hot Stars Radiative Torque and Partial Spin-Down of Winds from Rotating Hot Stars

Jul 2000

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2000apj...537..461g&link_type=abstract

The Astrophysical Journal, Volume 537, Issue 1, pp. 461-470.

Astronomy and Astrophysics

Astronomy

15

Hydrodynamics, Stars: Winds, Outflows

Scientific paper

We examine the degree to which the azimuthal component of the line-driving force can remove angular momentum from the equatorial wind of a rapidly rotating hot star, using a straightforward extension of the standard CAK formalism. We illustrate how even in a wind that is azimuthally symmetric, such a net azimuthal line force results from the prograde/retrograde velocity gradient asymmetries that are inherent to a non-rigidly rotating outflow. In particular, we show that the sense of the associated line torque always acts against the rotation whenever (as is generally the case) the azimuthal velocity falls below the linear outward increase (vφ~r) associated with rigid rotation. Through a parameter study based on two-dimensional numerical hydrodynamical simulations, we find that the net loss of wind angular momentum is significant but generally quite moderate, about 30%-40%, for a wide range of conditions. We then present an extensive analytic analysis that further illuminates the physical nature of the wind spin-down and its robust net magnitude. This emphasizes the inherent dynamical feedback between line driving and flow acceleration, which allows the radiative force to effectively amplify the Coriolis force in the rotating frame, and so cause the rotation speed to decrease even more steeply with radius than required to conserve angular momentum. A general conclusion is that, while the moderate net spin-down of the wind is not likely to have a major impact on the overall wind dynamics, it should be observable from emission line diagnostics, and that doing so would provide an independent test of line-driven wind theory.

Affiliated with

Also associated with

No associations

Rating

Radiative Torque and Partial Spin-Down of Winds from Rotating Hot Stars does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Radiative Torque and Partial Spin-Down of Winds from Rotating Hot Stars, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Radiative Torque and Partial Spin-Down of Winds from Rotating Hot Stars will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1717699