NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Analytic Lyman-alpha wing diagnostics and the chromospheric excitation balance in cool dwarfsI show that the Lyman alpha wings of cool dwarfs can be understood in terms of a very simple model, based on a simplified representation of the chromospheric hydrogen excitation balance and approximate analytic wing diagnostics in partial redistribution. Much of the complexity of the radiation transfer in the partially coherent and steeply temperature-sensitive Lyman alpha line is circumvented by this technique. The result is an expedient scheme for inverting the Lyman alpha wing profile to determine the characteristic free electron density and its gradient in the middle chromosphere. This represents an important new diagnostic for constraining chromospheric models and their radiative losses. I apply this diagnostic to the Lyman alpha wing profiles of the Sun and AU Mic and show that current instrumentation, most notably the Goddard High Resolution Spectrograph (GHRS) on the Hubble Space Telescope, is capable of providing the necessary data.
Document ID
19950029381
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Gayley, K. G.
(Univ. of Delaware, Newark, DE United States)
Date Acquired
August 16, 2013
Publication Date
August 20, 1994
Publication Information
Publication: The Astrophysical Journal
Volume: 431
Issue: 2 pt
ISSN: 0004-637X
Subject Category
Astrophysics
Accession Number
95A60980
Funding Number(s)
CONTRACT_GRANT: NSF AST-93-96069
CONTRACT_GRANT: NAGW-2994
CONTRACT_GRANT: NAGW-2568
Distribution Limits
Public
Copyright
Other

Available Downloads

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