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The Unusual UV Spectra of EUV-Discovered AM Herculis Stars

Published online by Cambridge University Press:  12 April 2016

Adrienne E. Herzog ,
Steve B. Howell  and
Keith O. Mason
Adrienne E. Herzog
Affiliation:
Planetary Science Institute, Astrophysics Group, 620 North Sixth Ave., Tucson AZ, 85705, USA
Steve B. Howell
Affiliation:
Planetary Science Institute, Astrophysics Group, 620 North Sixth Ave., Tucson AZ, 85705, USA
Keith O. Mason
Affiliation:
Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, Surrey RH5 6NT, UK

Abstract

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International Ultraviolet Explorer observations of the ROSATWFC-discovered AM Hers RE2107–05, RE1938–46, RE1833–74, RE1149+28, and RE0751+14 reveal UV spectra (1200 – 2000 Å) which are unique when compared with previously studied systems. Specifically, the intensities of individual emission lines due to CIV, CII, N V, HeII, and Si IV, are 2 – 4 times stronger then typically seen. However, the equivalent width ratios of these same emission lines, (CII/CIV, N V/CIV, HeII/CIV, and Si IV/CIV), are similar to those in typical AM Hers. These results indicate that the EUV-discovered AM Hers must have larger UV emitting volumes. Using additional observations of these stars made by EUVE, we speculate on the cause of their larger UV line fluxes.

Type
VI. Cataclysmic Variable Stars
Information
International Astronomical Union Colloquium , Volume 152: Astrophysics in the Extreme Ultraviolet , 1996 , pp. 361 - 365
Copyright
Copyright © Kluwer 1996

References

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