The ultraviolet spectrum of the high-field magnetic cataclysmic variable AR Ursae Majoris

D. W. Hoard; Gary D. Schmidt; Paula Szkody; Lilia Ferrario; Oliver Fraser; Michael A. Wolfe; B. T. Gänsicke

doi:10.1086/423918

The ultraviolet spectrum of the high-field magnetic cataclysmic variable AR Ursae Majoris

D. W. Hoard^*, Gary D. Schmidt, Paula Szkody, Lilia Ferrario, Oliver Fraser, Michael A. Wolfe, B. T. Gänsicke

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

7 Citations (Scopus)

Abstract

We have obtained an ultraviolet spectrum covering the range 917-1182 Å of the high-field magnetic cataclysmic variable AR Ursae Majoris when the binary was in its typical low-accretion state. The data reveal an array of deep Zeeman absorption features due to hydrogen Lyα-Lyγ, including several transitions that are normally forbidden but become enabled in the strong electric fields that exist in the atmospheres of highly magnetic white dwarfs. Spectral models indicate a magnetic field strength and structure consistent with that determined from longer wavelength Hubble Space Telescope Space Telescope Imaging Spectrograph UV observations; that is, a dipole of strength ∼235 MG offset along its axis by ∼0.15 of the stellar radius.

Original language	English
Pages (from-to)	1894-1898
Number of pages	5
Journal	Astronomical Journal
Volume	128
Issue number	4
DOIs	https://doi.org/10.1086/423918
Publication status	Published - Oct 2004

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title = "The ultraviolet spectrum of the high-field magnetic cataclysmic variable AR Ursae Majoris",

abstract = "We have obtained an ultraviolet spectrum covering the range 917-1182 {\AA} of the high-field magnetic cataclysmic variable AR Ursae Majoris when the binary was in its typical low-accretion state. The data reveal an array of deep Zeeman absorption features due to hydrogen Lyα-Lyγ, including several transitions that are normally forbidden but become enabled in the strong electric fields that exist in the atmospheres of highly magnetic white dwarfs. Spectral models indicate a magnetic field strength and structure consistent with that determined from longer wavelength Hubble Space Telescope Space Telescope Imaging Spectrograph UV observations; that is, a dipole of strength ∼235 MG offset along its axis by ∼0.15 of the stellar radius.",

keywords = "Novae, cataclysmic variables, Stars: individual (AR Ursae Majoris), Stars: magnetic fields, Ultraviolet: stars, White dwarfs",

author = "Hoard, \{D. W.\} and Schmidt, \{Gary D.\} and Paula Szkody and Lilia Ferrario and Oliver Fraser and Wolfe, \{Michael A.\} and G{\"a}nsicke, \{B. T.\}",

year = "2004",

month = oct,

doi = "10.1086/423918",

language = "English",

volume = "128",

pages = "1894--1898",

journal = "Astronomical Journal",

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publisher = "American Astronomical Society",

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T1 - The ultraviolet spectrum of the high-field magnetic cataclysmic variable AR Ursae Majoris

AU - Hoard, D. W.

AU - Schmidt, Gary D.

AU - Szkody, Paula

AU - Ferrario, Lilia

AU - Fraser, Oliver

AU - Wolfe, Michael A.

AU - Gänsicke, B. T.

PY - 2004/10

Y1 - 2004/10

N2 - We have obtained an ultraviolet spectrum covering the range 917-1182 Å of the high-field magnetic cataclysmic variable AR Ursae Majoris when the binary was in its typical low-accretion state. The data reveal an array of deep Zeeman absorption features due to hydrogen Lyα-Lyγ, including several transitions that are normally forbidden but become enabled in the strong electric fields that exist in the atmospheres of highly magnetic white dwarfs. Spectral models indicate a magnetic field strength and structure consistent with that determined from longer wavelength Hubble Space Telescope Space Telescope Imaging Spectrograph UV observations; that is, a dipole of strength ∼235 MG offset along its axis by ∼0.15 of the stellar radius.

AB - We have obtained an ultraviolet spectrum covering the range 917-1182 Å of the high-field magnetic cataclysmic variable AR Ursae Majoris when the binary was in its typical low-accretion state. The data reveal an array of deep Zeeman absorption features due to hydrogen Lyα-Lyγ, including several transitions that are normally forbidden but become enabled in the strong electric fields that exist in the atmospheres of highly magnetic white dwarfs. Spectral models indicate a magnetic field strength and structure consistent with that determined from longer wavelength Hubble Space Telescope Space Telescope Imaging Spectrograph UV observations; that is, a dipole of strength ∼235 MG offset along its axis by ∼0.15 of the stellar radius.

KW - Novae, cataclysmic variables

KW - Stars: individual (AR Ursae Majoris)

KW - Stars: magnetic fields

KW - Ultraviolet: stars

KW - White dwarfs

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U2 - 10.1086/423918

DO - 10.1086/423918

M3 - Article

SN - 0004-6256

VL - 128

SP - 1894

EP - 1898

JO - Astronomical Journal

JF - Astronomical Journal

IS - 4

ER -

The ultraviolet spectrum of the high-field magnetic cataclysmic variable AR Ursae Majoris

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