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Mass loss from red giants - A simple evolutionary model for NGC 7027NGC 7027 is a young planetary nebula with the remnants of a red giant circumstellar envelope surrounding the central, ionized region. By comparing the outer molecular envelope with the inner ionized material, it is argued that the mass loss rate has decreased by at least a factor of 3, and more probably by about a factor of 10, during the past 1000 years. From this result, it is argued that the luminosity of the central star has also decreased substantially during the same time, consistent with models for the rapid evolution of stars just after they evolve off the asymptotic giant branch. In this picture, the distance to NGC 7027 is less than 1300 pc. NGC 7027 was the last (and best) example of a star where apparently the momentum in the outflowing mass /M(dot)v/ is considerably greater than the momentum in the radiation field (L/c). With the above description of this object, the evidence is now strong that quite often the mass lost from late-type giants is ultimately driven to infinity by radiation pressure on grains. If M(dot)v is as large as L/c for asymptotic branch stars, then it is expected that the total amount of mass lost during this stage of evolution is of the same magnitude as the initial mass of the star, and therefore this mass loss can profoundly affect the star's ultimate fate.
Document ID
19850039076
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Jura, M. (California, University Los Angeles, CA, United States)
Date Acquired
August 12, 2013
Publication Date
November 15, 1984
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 286
ISSN: 0004-637X
Subject Category
ASTROPHYSICS
Distribution Limits
Public
Copyright
Other