The First Dynamical Mass Determination of a Nitrogen-rich Wolf-Rayet Star Using a Combined Visual and Spectroscopic Orbit - INSU - Institut national des sciences de l'Univers Accéder directement au contenu
Article Dans Une Revue The Astrophysical journal letters Année : 2021

The First Dynamical Mass Determination of a Nitrogen-rich Wolf-Rayet Star Using a Combined Visual and Spectroscopic Orbit

Noel D. Richardson
  • Fonction : Auteur
Laura Lee
  • Fonction : Auteur
Gail Schaefer
  • Fonction : Auteur
Tomer Shenar
  • Fonction : Auteur
Andreas A. C. Sander
  • Fonction : Auteur
Grant M. Hill
  • Fonction : Auteur
Andrew G. Fullard
  • Fonction : Auteur
John D. Monnier
  • Fonction : Auteur
Narsireddy Anugu
  • Fonction : Auteur
Claire L. Davies
  • Fonction : Auteur
Tyler Gardner
  • Fonction : Auteur
Stefan Kraus
  • Fonction : Auteur
Benjamin R. Setterholm
  • Fonction : Auteur

Résumé

We present the first visual orbit for the nitrogen-rich Wolf-Rayet binary, WR 133 (WN5o + O9I), based on observations made with the CHARA Array and the MIRC-X combiner. This orbit represents the first visual orbit for a WN star and only the third Wolf-Rayet star with a visual orbit. The orbit has a period of 112.8 days, a moderate eccentricity of 0.36, and a separation of a = 0.79 mas on the sky. We combine the visual orbit with an SB2 orbit and Gaia parallax to find that the derived masses of the component stars are ${M}_{{\rm{WR}}}=9.3\pm 1.6{M}_{\odot }$ and ${M}_{{\rm{O}}}=22.6\pm 3.2{M}_{\odot }$ , with the large errors owing to the nearly face-on geometry of the system combined with errors in the spectroscopic parameters. We also derive an orbital parallax that is identical to the Gaia-determined distance. We present a preliminary spectral analysis and atmosphere models of the component stars, and find the mass-loss rate in agreement with polarization variability and our orbit. However, the derived masses are low compared to the spectral types and spectral model. Given the close binary nature, we suspect that WR 133 should have formed through binary interactions, and represents an ideal target for testing evolutionary models given its membership in the cluster NGC 6871.

Dates et versions

insu-03705326 , version 1 (27-06-2022)

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Noel D. Richardson, Laura Lee, Gail Schaefer, Tomer Shenar, Andreas A. C. Sander, et al.. The First Dynamical Mass Determination of a Nitrogen-rich Wolf-Rayet Star Using a Combined Visual and Spectroscopic Orbit. The Astrophysical journal letters, 2021, 908, ⟨10.3847/2041-8213/abd722⟩. ⟨insu-03705326⟩
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