Estimating stellar wind parameters from low-resolution magnetograms

Moira Jardine, Aline Vidotto, Victor See

Research output: Contribution to journalArticlepeer-review

23 Citations (Scopus)


Stellar winds govern the angular momentum evolution of solar-like stars throughout their main-sequence lifetime. The efficiency of this process depends on the geometry of the star's magnetic field. There has been a rapid increase recently in the number of stars for which this geometry can be determined through spectropolarimetry. We present a computationally efficient method to determine the 3D geometry of the stellar wind and to estimate the mass-loss rate and angular momentum loss rate based on these observations. Using solar magnetograms as examples, we quantify the extent to which the values obtained are affected by the limited spatial resolution of stellar observations. We find that for a typical stellar surface resolution of 20o–30o, predicted wind speeds are within 5 per cent of the value at full resolution. Mass-loss rates and angular momentum loss rates are within 5–20 per cent. In contrast, the predicted X-ray emission measures can be underestimated by one-to-two orders of magnitude, and their rotational modulations by 10–20 per cent.
Original languageEnglish
Pages (from-to)L25-L29
JournalMonthly Notices of the Royal Astronomical Society: Letters
Issue number1
Early online date5 Oct 2016
Publication statusPublished - 11 Feb 2017


  • Magnetic fields
  • Stars: coronae
  • Stars: winds, outflow


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