Extreme resonance line profile variations in the ultraviolet spectra of NGC 1624-2: Probing the giant magnetosphere of the most strongly magnetized known O-type star

In this paper, we present high-resolution HST/COS observations of the extreme magnetic O star NGC 1624-2. These represent the first ultraviolet spectra of this archetypal object. We examine the variability of its wind-sensitive resonance lines, comparing it to that of other known magnetic O stars. In particular, the observed variations in the profiles of the C IV and Si IV doublets between low state and high state are the largest observed in any magnetic O-type star, consistent with the expected properties of NGC 1624-2's magnetosphere. We also observe a redshifted absorption component in the low state, a feature not seen in most stars. We present preliminary modelling efforts based on the Analytic Dynamical Magnetosphere (ADM) formalism, demonstrating the necessity of using non-spherically symmetric models to determine wind/magnetospheric properties of magnetic O stars.

This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society: © 2018 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

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Work Title Extreme resonance line profile variations in the ultraviolet spectra of NGC 1624-2: Probing the giant magnetosphere of the most strongly magnetized known O-type star
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Open Access
Creators
  1. A. David-Uraz
  2. C. Erba
  3. V. Petit
  4. A. W. Fullerton
  5. F. Martins
  6. N. R. Walborn
  7. R. MacInnis
  8. R. H. Barbá
  9. D. H. Cohen
  10. J. Máiz Apellaniz
  11. Y. Nazé
  12. S. P. Owocki
  13. J. O. Sundqvist
  14. A. ud-Doula
  15. G. A. Wade
Keyword
  1. Stars: early-type
  2. Stars: individual: NGC 1624-2
  3. Stars: magnetic field
  4. Stars: winds
  5. Outflows
  6. Ultraviolet: stars
License In Copyright (Rights Reserved)
Work Type Article
Publisher
  1. Monthly Notices of the Royal Astronomical Society
Publication Date November 28, 2018
Publisher Identifier (DOI)
  1. https://doi.org/10.1093/mnras/sty3227
Deposited January 25, 2024

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Version 1
published

  • Created
  • Added David-Uraz-NGC1624-2019-1.pdf
  • Added Creator A. David-Uraz
  • Added Creator C. Erba
  • Added Creator V. Petit
  • Added Creator A. W. Fullerton
  • Added Creator F. Martins
  • Added Creator N. R. Walborn
  • Added Creator R. MacInnis
  • Added Creator R. H. Barba
  • Added Creator D. H. Cohen
  • Added Creator J. Máiz Apellaniz
  • Added Creator Y. Naze
  • Added Creator S. P. Owocki
  • Added Creator J. O. Sundqvist
  • Added Creator A. Ud-Doula
  • Added Creator G. A. Wade
  • Published
  • Updated Keyword Show Changes
    Keyword
    • Stars: early-type, Stars: individual: NGC 1624-2, Stars: magnetic field, Stars: winds, Outflows, Ultraviolet: stars
  • Renamed Creator R. H. Barbá Show Changes
    • R. H. Barba
    • R. H. Barbá
  • Renamed Creator Y. Nazé Show Changes
    • Y. Naze
    • Y. Nazé
  • Renamed Creator A. ud-Doula Show Changes
    • A. Ud-Doula
    • A. ud-Doula
  • Updated