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V1016 Cygni, Spectral Observations 1968—1971

Published online by Cambridge University Press:  12 April 2016

M. Pim Fitzgerald

Abstract

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Identification of approximately 230 emission lines between 3120 Å and 5045 Å have been made on twelve plates taken between 1968 and 1971. The line intensities and ratios fail to give a consistent detailed picture of the nebula, but indicate that on average the electron pressure and density have changed little. The Balmer decrement has become less steep since 1968, indicating higher optical depth. However, the permitted iron lines have completely gone, indicating lower density. Excitation is increasing in some parts of the nebula, as indicated by the increased strength of the [Fe V] lines, and the recent appearance of strong lines of [Ne Y]. The continuum remains weak, though it is easily seen on plates taken on April 8, 1969, and on those taken in June 1971. The radial velocity of the object fluctuates between —50 and — 70 km/sec, and the line widths remain about 120 km/sec. The wing to the violet of the emission lines is still present. The continued brightness of this object, and the relative lack of change in the spectrum over several years, indicate even more strongly that V 1016 Cygni is likely to be a planetary nebula in the stages of formation.

Type
I. New Phenomena in Very Cool, or Very Young, or Very Peculiar Variables
Information
International Astronomical Union Colloquium , Volume 15: New Directions and Frontiers in Variable Stars Research , 1971 , pp. 73 - 84
Copyright
Copyright © Cambridge University Press 1971

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