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Simultaneous Five Color (Ubvri) Polarimetry of EF Eri*

Published online by Cambridge University Press:  12 April 2016

V. Piirola ,
A. Reiz  and
G.V. Coyne
V. Piirola
Affiliation:
Vatican Observatory, Città del Vaticano on leave from , University of Helsinki Observatory
A. Reiz
Affiliation:
University Observatory, Copenhagen, Denmark
G.V. Coyne
Affiliation:
Vatican Observatory, Città del Vaticano

Abstract

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We present the first observations of the AM Her type object EF Eri where both the polarization and the photometric data are recorded simultaneously in five color bands (UBVRI). The position angle rotates strongly (~30° ) vs. wavelength from U to 1, probably due to Faraday rotation or due to fact that the polarized radiation seen in the different wavelength bands comes from different parts of the accretion region. The phase dependence of the position angle requires field and accretion geometry more complicated than a simple centered dipole and a second emitting region producing weaker intermediate pulses in the infrared seems to be present. We derive the value of the inclination of the system i = 55° ± 5° , the colatitude of the active pole βl = 38° ± 5° i and the second emitting region β2 = 115° ± 5° , both of which are nearly at the same longitude facing the main accretion stream.

Type
II. Radio, IR and Optical Observations
Information
International Astronomical Union Colloquium , Volume 93: Cataclysmic Variables: Recent Multi-Frequency Observations and Theoretical Developments , 1987 , pp. 197 - 201
Copyright
Copyright © Reidel 1987

Footnotes

*

Based on observations made at the European Southern Observatory, La Silla, Chile.

References

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