A “flash spectrum” of cool absorption in 31 CYGNI: A direct observation of the reversing layer?

  • Imad A. Ahmad
Re-examining the Corona/Wind Dividing Line
Part of the Lecture Notes in Physics book series (LNP, volume 291)


We report the discovery of narrow absorption lines due to low temperature ions, äpparantly in the “reversing layer” of the supergiant component of a zeta Aur type binary. We have measured the radial velocities and equivalent widths of thirteen of these lines near ingress and egress and find a three sigma upper limit on the rotational velocity of the supergiant along the line of sight of 6 km/s.


Radial Velocity Rotational Velocity Equivalent Width Systemic Velocity Local Interstellar Medium 
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  3. Kelly, R.L., and Palumbo, L.J. 1973, Atomic and Ionic Emission Lines Below 2000 Angstroms (Washington, D.C.: NRL).Google Scholar
  4. Wright, K.O. 1970, Vistas in Astr., 12, 147.Google Scholar

Copyright information

© Springer-Verlag 1987

Authors and Affiliations

  • Imad A. Ahmad
    • 1
  1. 1.Imad-ad-Dean, Inc.BethesdaUSA

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