Temporal variability of the wind from the star τ Boötis - INSU - Institut national des sciences de l'Univers Access content directly
Journal Articles Monthly Notices of the Royal Astronomical Society Year : 2016

Temporal variability of the wind from the star τ Boötis

B. A. Nicholson
  • Function : Author
A. A. Vidotto
  • Function : Author
M. Mengel
  • Function : Author
L. Brookshaw
  • Function : Author
B. Carter
  • Function : Author
S. C. Marsden
  • Function : Author
S. V. Jeffers
  • Function : Author
R. Fares
  • Function : Author


We present new wind models for τ Boötis (τ Boo), a hot-Jupiter-host-star whose observable magnetic cycles makes it a uniquely useful target for our goal of monitoring the temporal variability of stellar winds and their exoplanetary impacts. Using spectropolarimetric observations from May 2009 to January 2015, the most extensive information of this type yet available, to reconstruct the stellar magnetic field, we produce multiple 3D magnetohydrodynamic stellar wind models. Our results show that characteristic changes in the large-scale magnetic field as the star undergoes magnetic cycles produce changes in the wind properties, both globally and locally at the position of the orbiting planet. Whilst the mass loss rate of the star varies by only a minimal amount (∼4 per cent), the rates of angular momentum loss and associated spin-down time-scales are seen to vary widely (up to ∼140 per cent), findings consistent with and extending previous research. In addition, we find that temporal variation in the global wind is governed mainly by changes in total magnetic flux rather than changes in wind plasma properties. The magnetic pressure varies with time and location and dominates the stellar wind pressure at the planetary orbit. By assuming a Jovian planetary magnetic field for τ Boo b, we nevertheless conclude that the planetary magnetosphere can remain stable in size for all observed stellar cycle epochs, despite significant changes in the stellar field and the resulting local space weather environment.
Fichier principal
Vignette du fichier
stw731.pdf (2.9 Mo) Télécharger le fichier
Origin : Publisher files allowed on an open archive

Dates and versions

insu-03669484 , version 1 (16-05-2022)



B. A. Nicholson, A. A. Vidotto, M. Mengel, L. Brookshaw, B. Carter, et al.. Temporal variability of the wind from the star τ Boötis. Monthly Notices of the Royal Astronomical Society, 2016, 459, pp.1907-1915. ⟨10.1093/mnras/stw731⟩. ⟨insu-03669484⟩
13 View
7 Download



Gmail Facebook Twitter LinkedIn More