Statistical relations between spectropolarimetric observables and the polar strength of the stellar dipolar magnetic field
Abstract
Global magnetic fields of earlytype stars are commonly characterised by the mean longitudinal magnetic field <B_{z}> and the mean field modulus , derived from the circular polarisation and intensity spectra, respectively. Observational studies often report a root mean square (rms) of <B_{z}> and an average value of . In this work, I used numerical simulations to establish statistical relationships between these cumulative magnetic observables and the polar strength, B_{d}, of a dipolar magnetic field. I show that in the limit of many measurements randomly distributed in rotational phase, <B_{z}>_{rms} = 0.179_{−0.043}^{+0.031} B_{d} and _{avg} = 0.691_{−0.023}^{+0.020} B_{d}. The same values can be recovered with only three measurements, provided that the observations are distributed uniformly in the rotational phase. These conversion factors are suitable for ensemble analyses of large stellar samples, where each target is covered by a small number of magnetic measurements.
 Publication:

Astronomy and Astrophysics
 Pub Date:
 June 2024
 DOI:
 10.1051/00046361/202449459
 arXiv:
 arXiv:2404.17517
 Bibcode:
 2024A&A...686A.189K
 Keywords:

 techniques: polarimetric;
 stars: earlytype;
 stars: magnetic field;
 Astrophysics  Solar and Stellar Astrophysics
 EPrint:
 5 pages, 3 figures