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The Hα profile in Zeta Puppis

Published online by Cambridge University Press:  14 August 2015

David Van Blerkom*
Affiliation:
Joint Institute for Laboratory Astrophysics, University of Colorado and National Bureau of Standards, Boulder, CO 80309

Extract

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The Hα profile in the spectrum of Zeta Puppis is shown in Figure 1 (Conti and Frost 1977). It is of the P Cygni type, with a violet displaced absorption component that extends to about 300 km s−1 from line center. An unusual feature is the broad wing emission which can be seen out to 1500 km s−1 on both sides of the line. Of the roughly 2.5 Å equivalent width of Hα, 1.8 Å is due to velocity displacements |δv| > 300 km s−1. The presence of wing emission shortward of the violet absorption edge has been noted before in a Wolf-Rayet star, where it is attributed to non-coherent electron scattering (Castor, Smith and Van Blerkom 1970). In the present case, an optical depth in electrons of nearly 1.5 is required to produce the extensive wings by scattering a normal P Cygni profile. This exceeds by a factor of three the electron scattering optical thickness through the entire envelope, assuming published values of the mass loss rate, terminal velocity of the wind and photospheric radius. Thus an alternative explanation is required.

Type
Session 5: Theory and Mass Loss Rates Binary Stars - Miscellaneous Topics
Copyright
Copyright © Reidel 1979 

References

Castor, J.I., Smith, L.F. and Van Blerkom, D.: 1970, Ap. J., 159, p. 1119.CrossRefGoogle Scholar
Conti, P.S. and Frost, S.A.: 1977, Ap. J., 212, p. 728.CrossRefGoogle Scholar