NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Physical Theories of Winds From Cool StarsCool stars in the late stages of their evolution generally lose mass at a prodigious rate. This includes low mass stars on the red giant branch, on the asymptotic giant branch, and those transiting from the asymptotic giant branch to the planetary nebula phase, as well as massive supergiants. All of these objects are surrounded by dense circumstellar gas and often dust envelopes. This mass loss is an important source of gas and dust for the interstellar medium. For some of these objects, the mass loss rate exceeds the nuclear burning rate and, hence, mass loss determines the subsequent evolution of the star. A variety processes have been invoked to explain the mass loss of these objects. A consensus has developed over the last decade: photospheric processes create an extended atmosphere which extends to several stellar radii. At this height above the photosphere, dust grains can form and radiation pressure drives the dust out. The gas is dragged along by friction. While the detailed processes involved, in particular those lifting the atmosphere, may differ from object to object, this paradigm seems applicable to all of these objects. The process of mass loss breaks up into three parts: 1) The formation of the extended atmosphere; 2) the nucleation and condensation of dust; and 3) The radiation pressure driven wind. Each of these processes will be discussed with an emphasis on those processes that play a role in the mass loss from asymptotic giant branch stars for which the most detailed theories have been developed.
Document ID
20020024910
Acquisition Source
Ames Research Center
Document Type
Preprint (Draft being sent to journal)
Authors
Tielens, A. G. G. M.
(NASA Ames Research Center Moffett Field, CA United States)
Cuzzi, Jeffrey N.
Date Acquired
August 20, 2013
Publication Date
January 1, 1994
Subject Category
Astrophysics
Funding Number(s)
PROJECT: RTOP 399-20-10-27
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

Available Downloads

There are no available downloads for this record.
No Preview Available